Ch. 10 – PSY 350

control variable
a potential variable that an experimenter holds constant on purpose
comparison group
a group in an experiment whose level on the independent variable differs from those of the treatment group in some intended and meaningful way. also called comparison condition
control group
a level of an independent variable that is intended to represent “no treatment” or a neutral condition
treatment group
the participants in an experiment who are exposed to the level of the independent variable that involves a medication, therapy or intervention
placebo group
a control group that is exposed to an intern treatment
confound
a general term for a potential alternative explanation for a research finding
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design confound
a threat to internal validity in an experiment to which a second variable happens to vary systematically along with the independent variable and therefore is an alternative explanation for the results
systematic variability
in an experiment, the levels of a variable coinciding in some predictable way with experimental group membership, creating a potential confound
unsystematic variability
in an experiment, when levels of a variable fluctuate independently of experimental group membership, contributing to variability within groups
selection effect
a threat to internal validity that occurs in an independent groups design when the kinds of participants at one level of the independent variable are systematically different from those at the other level
matched groups
an experimental design technique in which participants who are similar on some measured variable are grouped into sets; the members of each matched set are then randomly assigned to different experimental conditions (also called matching)
independent-groups design
an experimental design in which different groups of participants are exposed to different levels of the independent variable, such that each participants experiences only one level of the independent variable (also called between-subjects design)
within-groups design
an experimental design in which each participant is presented with all levels of the independent variable
post test only design
an experiment using an independent-groups design in which participants are tested on the dependent variable only once
pretest/post test design
an experiment using an independent-groups design in which participants are tested on the key dependent variable twice, once before and once after exposure to the independent variable.
concurrent measures design
an experiment using a within groups design in which participants are exposed to all the levels of an independent variable at roughly the same time, and a single attitudinal or behavioral preference is the dependent variable
repeated measures design
an experiment using a within groups design in which participants respond to a dependent variable more than once, after exposure to each level of the independent study
power
the likelihood that a study will show a statistically significant result when some effect is truly present in the population; the probability of not making a type 2 error
order effect
in a within-groups design, a threat to internal validity in which exposure to one contain changes participants responses to a later
practice effect
a type of order effect in which people’s performance improves over time because they become practiced at the dependent measure (not because of the manipulation or treatment)
carryover effect
a type of order effect in which some form of contamination carries over from one condition to the next
counterbalancing
in a repeated measures experiment, presenting the levels of the independent variable to participants in different sequences to control fro order effects
full counterbalancing
a meth0d of counterbalancing in which all possible condition orders are represented
partial counterbalancing
a method of counterbalancing in which some, but not all, of the possible condition orders are represented.
latin square
a formal system of partial counterbalancing that ensures that each condition in a within-groups design appears in each position at least once
demand characteristics
a threat to internal validity that occurs when some cue leads participants to guess a study’s hypotheses or goals
manipulation check
in an experiment, an extra dependent variable researchers can include to determine how well an experimental manipulation worked
pilot study
a study completed before the study of primary interest, usually to test the effectiveness or characteristics of the manipulations
Cara is running a study to examine the effect of music on mood. She randomly assigns participants to three conditions — rock, jazz, and country. She has the participants rate their mood with a short questionnaire, then listen to their assigned music for 20 minutes, and then fill out the mood questionnaire again. What kind of design is she using
pretest/posttest
What is the name for a variable that the experimenter holds constant on purpose?
control variable
What is the name for the level of the independent variable that is intended to represent a neutral condition?
control group
Participants in a research study are given a list of words to study for 3 minutes and then, following a delay, are asked to recall the list. The length of the delay is manipulated between participants to be either 2 minutes, 5 minutes, or 10 minutes. Which of the following scenarios would present a design confound in this experiment?
All participants in the 2-minute condition are tested at 8:00 a.m.; those in the 5-minute condition are tested at noon; and those in the 10-minute condition are tested at 4:00 p.m.
____________ is an extra dependent variable that can be used to help researchers quantify how well an experimental manipulation worked
A manipulation check
experiment
researchers manipulated at least one variable and measured another.
manipulated variable
a variable that is controlled. (Independent Variable)
measured variables
take the form of records of behaviors or attitudes, such as self-reports, behavioral observations, or physiological measures. (Dependent Variable)
Conditions
One of the levels of the independent variable in an experiment. Similar enough to also be known as a variable’s levels.
Dependent Variable
outcome variable. How a participant acts on the measured variable depends on the level of the independent variable.
On a graph, how can you tell which is the I.V. and which is the D.V.?
The independent variable is almost always on the x-axis, and the dependent variable is almost always on the y-axis.
Control variable
A potential variable that an experimenter holds constant on purpose.
When researchers manipulate a variable, they need to make sure they are only varying one thing at a time. Researchers control potential third variables in their studies by holding all other factors constant. Any variable that the experimenter holds constant on purpose is called the control variable.
Control variables are important for establishing internal validity
What are the minimum requirements for a study to be an experiment?
To be an experiment the study must have at least one measured and one manipulated variable.
Define IV, DV, and Control Variable using your own words.
IV: manipulated variable
DV: measured variable
CV: variable held constant to rule out third variables and establish internal validity.
comparison group
A group in an experiment whose levels on the independent variable differ from those of the treatment group in some intended and meaningful way. Also called comparison condition.
control group
A level of an independent variable that is intended to represent ‘ no treatment ‘ or a neutral condition.
Treatment group(s)
The participants in an experiment who are exposed to the level of the independent variable that involves a medication, therapy, or intervention.
placebo group/placebo control group
When the control group is exposed to an inert treatment such as a sugar pill
Why are experiments useful?
Experiments establish covariance.
Experiments establish temporal precedence. The ability to establish temporal precedence is a feature that makes experiments superior to correlational designs.
Well-designed experiments establish internal validity. To be internally valid, a study must ensure that the causal variable and not other factors, is responsible for the change in the effect variable.
Confounds
A general term for a potential alternative explanation for a research finding (a threat to internal validity).
For any given research question, there can be several possible alternative explanations.
design confound
An experimenter’s mistake in designing the independent variable; it is a second variable that happens to vary systematically along with the intended independent variable and therefore is an alternative explanation for the results.
Can be a threat to internal validity
Systematic variability
In an experiment, the levels of a variable coinciding in some predictable way with experimental group membership, creating a potential confound
Unsystematic variability
In an experiment, when levels of a variable fluctuate independently of experimental group membership, contributing to variability within groups. (random or haphazard variability across both groups)
Unsystematic variability can lead to problems; it can obscure, or make it difficult to detect differences in the dependent variable.
selection effect
Occurs when the kinds of participants in one level of the independent variable are systematically different from those in the other.
Can occur when experimenters let participants chose which group they want to be in. EX: letting parents chose which group they would like their autistic children to be in, the intensive treatment group, or the usual treatment group.
Random Assignment
The use of a random method (e.g., flipping a coin) to assign participants into different experimental groups.
A way of desystematizing the types of participants who end up in each level of the independent variable.
Used to avoid selection effects
Matched groups
An experimental design technique in which participants who are similar on some measured variable are grouped into sets; the members of each matched set are then randomly assigned to different experimental conditions.
This method is particularly useful if the experiment’s design has outliers (exceptionally clever or inept participants) and if the sample groups are small in size.
This method also ensures that the groups are equal on some important variable, such as IQ, before the manipulation of the independent variable.
Independent – Groups Design
Different groups of participants are placed into different levels of the independent variable.
An experimental design in which different groups of participants are exposed to different levels of the independent variable, such that each participant experiences only one level of the independent variable
AKA between-subjects design or between-groups design
2 Basic forms of independent-groups designs are the posttest-only design and the pretest/posttest design.
Within-Groups design/ Within – Subjects Design
There is only one group of participants, and each person is presented with all levels of the independent variable
posttest – only design / equivalent groups
participants are randomly assigned to independent variable groups and are tested on the dependent variable once.
An experiment using an independent-groups design in which participants are tested on the dependent variable only once. Also called equivalent groups, posttest-only design.
pretest/pottest design
Participants are randomly assigned to at least two groups and are tested on the key dependent variable twice – once before and once after exposure to the independent variable.
Researchers might do this if they want to evaluate whether random assignment made the groups equal
This design also works well to track how participants in the experimental groups have changed over time in response to some manipulation.
What is the difference between independent groups and within groups designs?
The number of levels of the independent variable the participants are exposed to. In a within groups design they are exposed to all levels, in an independent groups design they are only exposed to one level.
Concurrent – measures design
Participants are exposed to all the levels of an independent variable at roughly the same time, and a single attitudinal or behavioral preference is the dependent variable.
EX: babies shown male and female faces at the same time. The babies chose to look at the female face more often than not.
Repeated – measures design
A within groups design in which participants are measured on a dependent variable more than once – that is, after exposure to each level of the independent variable.
EX: participant –> interact with own toddler –> measure oxytocin levels –> interact with new toddler —> measure oxytocin level.
What are some advantages of within groups designs?
It ensures the participants in the two groups will be equivalent (because they are the same people). Variations among participants will not effect results because their scores are only rated against themselves and not others. Statistically speaking, extraneous differences in personality, living conditions, gender, ability etc are held constant across all conditions, so researchers will be more likely to detect an effect of the independent variable manipulation if there is one.

Generally requires fewer participants overall.

power
Refers to the ability of a study to show a statistically significant result when an independent variable truly has an effect in the population.
order effects
Being exposed to one condition changes how participants react to the other condition
Happen when exposure to one level of the independent variable influences responses to the next level of the independent variable.`
practice effects/fatigue effects
A long sequence might lead participants to get better at the task, or to get tired or bored towards the end.
carryover effects
Some form of contamination carries over from one condition to the next.
counterbalancing
When researchers use counterbalancing, they present the levels of the independent variable to participants in different orders. With counterbalancing, any order effects should cancel each other out when all the data are collected.
full counterbalancing
all possible condition orders are represented.
Ex: A – B- C, A – C- B, B – A – C, B – C- A, C – A – B, C – B – A
2 conditions = 2 orders
3 conditions = 6 orders
4 conditions = 24 orders
Partial counterbalancing
Only some of the possible condition orders are represented. One way to partially counterbalance is to present the conditions in a randomized order for each subject.
Latin Square
A formal system of partial counterbalancing that ensures that each condition in a within – groups design appears in each position at least once.
The first row is set up according to a formula, and then the conditions simply go in numerical order down each column
What are the three main disadvantages of within – groups designs?
Repeated Measures designs have the potential for order effects, which can threaten internal validity. (Can be controlled for using counterbalancing)
Might not be possible/practical. (such as teaching children to ride a bike. You teach them with method A, you cannot go back to the baseline and teach them with method B.
People might change the way they act if they see all levels of the independent variable. (Demand characteristics)
Demand Characteristics aka Experimental Demand
When an experiment contains cues that lead participants to guess its hypothesis.
what are two simple forms of within – groups designs?
Concurrent measures
repeated measures
Describe how counterbalancing improves the internal validity of a within – groups design?
With counterbalancing, any order effects should cancel each other out when all the data are collected.
Summarize the three advantages and the three potential disadvantages of within – groups designs
Advantages:
assurance of equivalence of the groups
requirement of fewer participants
more statistical power

Disadvantages:
Participants cannot be returned to their original state after each condition.
Demand characteristics may result from hypothesis guessing with repeated testing.
Order effects can threaten internal validity.

manipulation check
an extra dependent variable that researchers can insert into an experiment to help them quantify how well an experimental manipulation worked.
Pilot Study
a simple study, using a separate group of participants, that is completed before (or sometimes after) conducting the stufy of primary interest. Researchers might use pilot study data to confirm the effectiveness of their manipulations.
Describe Cohen’s guidelines for effect size strength
.20 = small or weak comparable to an r of .10
.50 = medium, or moderate comparable to an r of .30
.80 = large or strong comparable to an r of .50
Cara is running a study to examine the effect of music on mood. She randomly assigns participants to three conditions — rock, jazz, and country. She has the participants rate their mood with a short questionnaire, then listen to their assigned music for 20 minutes, and then fill out the mood questionnaire again. What kind of design is she using?

posttest only

pretest/posttest

concurrent measures

repeated measures

b
Dr. Keller wants to test the effect of a new anti-anxiety medication. He recruits a group of anxious patients and randomly assigns them to two groups. One group will receive his new medication and the other will receive a sugar pill. What is the second group called?

treatment group

placebo group

experimental group

manipulation group

b
What is the name for a variable that the experimenter holds constant on purpose?

dependent variable

independent variable

control variable

confound variable

c
What is the name for the level of the independent variable that is intended to represent a neutral condition?

treatment group

manipulation group

experimental group

control group

d
Participants in a research study are given a list of words to study for 3 minutes and then, following a delay, are asked to recall the list. The length of the delay is manipulated between participants to be either 2 minutes, 5 minutes, or 10 minutes. Which of the following scenarios would present a design confound in this experiment?

All participants in the 2-minute condition are tested at 8:00 a.m.; those in the 5-minute condition are tested at noon; and those in the 10-minute condition are tested at 4:00 p.m.

The same list is used for each condition and is randomized for each participant.

The three groups are run simultaneously in three different rooms, and the room for each condition is randomly chosen before each group arrives.

Three different experimenters are in charge of administering the task, and they rotate which condition they are administering.

a
Participants in a research study are given a list of words to study for 3 minutes and then, following a delay, are asked to recall the list. The length of the delay is manipulated between participants to be either 2 minutes, 5 minutes, or 10 minutes. Since different groups need different amounts of time, the first 25 participants who arrive are assigned to the 10-minute group, the next 25 are assigned to the 5-minute group, and the final 25 are assigned to the 2-minute group. What confound does this create?

demand characteristic

selection effect

experimenter bias

carryover effect

b
Kathryn wants to control for intelligence in her study. She has a list of all of the participants for her study and their IQ scores. She sorts the list of participants according to their IQ scores and then forms groups making sure that the groups are balanced in terms of IQ scores. Finally, she randomly assigns each group to one of the conditions of her study. What kind of design is Kathryn using?

independent groups

concurrent measures

matched-groups

within-groups

c
What design is an experiment in which each participant is randomly assigned to one level of the independent variable and then tested on the dependent variable once?

within-groups

repeated measures

pretest/posttest

posttest only

d
Which of these is NOT an advantage of within-groups designs?

elimination of practice effects

assurance of equivalence of the groups

requirement of fewer participants

more statistical power

a
Which of the following does NOT need to be considered as an alternative explanation of the results in a within-groups design experiment?

order effects

selection effects

practice effects

carryover effects

b
How many possible orders for full counterbalancing are there in a study with four conditions?

four

eight

sixteen

twenty-four

d
Eric designs a study to examine drink preferences of university freshmen. He is planning to have all of the freshmen who participate in his study drink a cup of coffee then rate their enjoyment of the coffee, then drink a cup of tea and rate their enjoyment of the tea, and finally drink a cup of milk and rate their enjoyment of the milk. Eric tells Theresa about the plans for his study and she says she is concerned that he could have a problem with order effect in his study. How can Eric fix this problem?

matched groups

random sampling

counterbalancing

random assignment

c
Which of these is NOT a potential drawback of a within-groups design?

Extraneous differences are held constant across conditions.

Participants cannot be returned to their original state after each condition.

Demand characteristics may result from hypothesis guessing with repeated testing.

Order effects can threaten internal validity.

a
Eric designs a study to examine drink preferences of university freshmen. He is planning to have all of the freshmen who participate in his study drink a cup of coffee then rate their enjoyment of the coffee, then drink a cup of tea and rate their enjoyment of the tea, and finally drink a cup of milk and rate their enjoyment of the milk. What kind of design is this?

posttest only

pretest/posttest

concurrent measures

repeated measures

d
According to Cohen’s conventions for effect size, how do you describe an effect size when d = 0.50?

not existent

weak

moderate

strong

c
In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated-measures design. What is the independent variable in this experiment?

depth perception

number of trials

disparity from perfect alignment

eye/eyes used

d
In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated-measures design. What is the dependent variable in this experiment?

distance out of alignment of the rods

how long the participant takes to complete the experiment

improvement in performance by the participant

eye/eyes used

a
In an experiment, researchers:

measure more than two variables.

measure two variables.

manipulate two variables.

manipulate one variable and measure another.

d
In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated-measures design. She finds that d = 1.53. What effect size is this?

weak

moderate

strong

This cannot be determined without knowing the number of participants.

c
In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated-measures design. How is the independent variable being manipulated in Tetiana’s design?

independent groups

within-groups

concurrently

as a participant variable

b
In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept for the mug. What is the independent variable in this experiment?

role of the participant

price that the buyer will pay

price that the seller will accept

type of mug

a
In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept for the mug. What is the dependent variable in this experiment?

role of the participant

value selected for the mug

type of mug

the range of prices that the buyer and seller each consider

b
In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept for the mug. How does Theo control for selection effects?

by using a control group

by using matched-groups design

by using random assignment of participants

by using a pretest/posttest design

c
__________ is a simple study that uses a separate group of participants that is generally completed before conducting the study of primary interest in order to confirm the effectiveness of a manipulation.

A pilot study

A Latin square

Counterbalancing

A manipulation check

a
____________ is an extra dependent variable that can be used to help researchers quantify how well an experimental manipulation worked.

A pilot study

A Latin square

Counterbalancing

A manipulation check

d
Carryover Effect
A type of order effect, in which some form of contamination carries over from one condition to the next
Comparison Group
A group in an experiment whose levels on the independent variable differ from those of the treatment group in some intended and meaningful way. AKA: Comparison Condition
Concurrent-Measure
An experiment using a with-in groups design in which participants are exposed to all the levels of an independent variable at roughly the same time, and a single attitudinal or behavioral preference is the dependent variable.
Condition
One of the levels of the independent variable in an experiment.
Confound
A general term for a potential alternative explanation for a research finding (a threat to internal validity).
Control Group
A level of an independent variable that is intended to represent “no treatment” or neutral condition.
Control Variable
A potential variable that an experimenter holds constant on purpose.
Counterbalancing
In an experiment, presenting the levels of the independent variable to participants in different sequences to control for order effects.
Demand Characteristic
A threat to internal validity that occurs when some cue leads participants to guess a study’s hypotheses or goals. AKA: experimental demand
Dependent Variable
In an experiment, the variable that is measured. In a multiple-regression analysis, the single outcome, or criterion variable, the researchers are most interested in understanding or predicting. AKA: outcome variable
Design Confound
A threat to internal validity in an experiment in which a second variable happens to vary systematically along with the independent variable and therefore is an alternative explanation for the results.
Experiment
A study in which one variable is manipulated and the other is measured.
Full Counterbalancing
A method of counterbalancing in which all possible condition orders are represented.
Independent-Groups Design
An experimental design in which different groups of participants are exposed to different levels of the independent variable, such that each participant experiences only one level of the independent variable. AKA: between-subjects design or between-groups design
Independent Variable
A variable that is manipulated in an experiment. In a multiple-regression analysis, a predictor variable used to explain variance in the criterion variable.
Latin Square
A formal system of partial counterbalancing that ensures that each condition in a within-groups design appears in each position at least once.
Manipulated Variable
A variable in an experiment that a researcher controls, such as by assigning participants to its different levels (values).
Manipulation Check
In an experiment, an extra dependent variable researchers can include to determine how well an experimental manipulation worked.
Matched Groups
An experimental design technique in which participants who are similar on some measured variable are grouped into sets; the members of each matched set are then randomly assigned to different experimental conditions. AKA: matching
Measured Variable
A variable in an experiment whose levels (values) are observed and recorded.
Order Effect
In a within-groups design, a threat to internal validity in which exposure to one condition changes participants’ responses to a later condition.
Partial Counterbalancing
A method of counterbalancing in which some, but not all, of the possible condition orders are represented.
Pilot Study
A study completed before (or sometimes after) the study of primary interest, usually to test the effectiveness or characteristics of the manipulations.
Placebo Group
A control group that is exposed to an inert treatment (e.g., a sugar pill). AKA: placebo control group
Posttest-only Design
An experiment using an independent-groups design in which participants are tested on the dependent variable only once. AKA: equivalent groups, posttest-only design
Power
The likelihood that a study will show a statistically significant result when some effect is truly present in the population; the probability of not making a Type II error when the null hypothesis is false.
Practice Effect
A type of order effect in which people’s performance improves over time because they become practiced at the dependent measure (not because of the manipulation or treatment).
Pretest/Posttest Design
An experiment using an independent-groups design in which participants are tested on the key dependent variable twice: once before and once after exposure to the independent variable.
Random Assignment
The use of a random method (e.g., flipping a coin) to assign participants into different experimental groups.
Repeated-Measures Design
An experiment using a within-groups design in which participants respond to a dependent variable more than once, after exposure to each level of the independent variable.
Selection Effect
A threat to internal validity that occurs in an independent-groups design when the kinds of participants at one level of the independent variable are systematically different from those at the other level.
Systematic Variability
In an experiment, the levels of a variable coinciding in some predictable way with experimental group membership, creating a potential confound.
Treatment Group
The participants in an experiment who are exposed to the level of the independent variable that involves a medication, therapy, or intervention.
Unsystematic Variability
In an experiment, when levels of a variable fluctuate independently of experimental group membership, contributing to variability within groups
Within-Groups Design
An experimental design in which each participant is presented with all levels of the independent variable. Also called within-subjects design.
In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept for the mug. What is the dependent variable in this experiment?
Value selected for the mug

-The value of the mug is the measured variable

Which of the following does NOT need to be considered as an alternative explanation of the results in a within-groups design experiment?
Selection Effects

-Selection effects only apply to independent-groups designs

In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept for the mug. What is the independent variable in this experiment?
Role of the participant

-Theo assigns the participants to their roles, so that is the manipulated variable

What is the name for the level of the independent variable that is intended to represent a neutral condition?
Control Group

-The group that represents “no treatment” or the neutral condition is the control group

In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated-measures design. What is the dependent variable in this experiment?
Distance out of alignment of the rods

-Tetiana is measuring how far out of alignment the rods are, making that the dependent variable.

Eric designs a study to examine drink preferences of university freshmen. He is planning to have all of the freshmen who participate in his study drink a cup of coffee then rate their enjoyment of the coffee, then drink a cup of tea and rate their enjoyment of the tea, and finally drink a cup of milk and rate their enjoyment of the milk. Eric tells Theresa about the plans for his study and she says she is concerned that he could have a problem with order effect in his study. How can Eric fix this problem?
Counterbalancing

-Eric could avoid an order effect by having participants consume and rate the drinks in varying orders

____________ is an extra dependent variable that can be used to help researchers quantify how well an experimental manipulation worked.
A manipulation Check

-Manipulation checks help researchers measure how well their manipulation worked

In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated-measures design. She finds that d = 1.53. What effect size is this?
Strong

-her findings give a d well above 0.80, so the effect size is strong

How many possible orders for full counterbalancing are there in a study with four conditions?
Twenty-four

-For full counterbalancing, all the possible condition orders must be used, which is 24 for four conditions

What design is an experiment in which each participant is randomly assigned to one level of the independent variable and then tested on the dependent variable once?
Posttest only

-The participants are randomly assigned to the groups and only a posttest is administered

Experiment
A study in which one variable is manipulated and the other is measured
Manipulated Variable
A variable in an experiment that a researcher controls, such as by assigning participants to its different levels (values).
measured variable
A variable in an experiment whose levels (values) are observed and recorded
independent variable
A variable that is manipulated in an experiment. In a multiple-regression analysis, a predictor variable used to explain variance in the criterion variable.
condition
One of the levels of the independent variable in an experiment
dependent variable
An an experiment, the variable that is measured. In a multiple-regression analysis, the single outcome, or criterion variable, the researchers are most interested in understanding or predicting
control variable
A potential variable that an experimenter holds constant on purpose.
comparison group
A group in an experiment whose level on the independent variable differs from those of the treatment group in some intended and meaningful way.
control group
A level of an independent variable that is intended to represent “no treatment” or a neutral condition.
treatment group
The participants in an experiment who are exposed to the level of the independent variable that involves a medication, therapy, or intervention.
placebo group
A control group that is exposed to an inert treatment (e.g. a sugar pill).
confound
A general term for a potential alternative explanation for a research finding (a threat to internal validity).
design confound
A threat to internal validity in an experiment in which a second variable happens to vary systematically along with the independent variable and therefore is an alternative explanation for the results.
systemic variability
In an experiment, the levels of a variable coinciding in some predictable way with experimental group membership, creating a potential confound.
unsystematic variability
In an experiment, when levels of a variable fluctuate independently of experimental group membership contributing to variability within groups.
selection effect
A threat to internal validity that occurs in an independent-groups design when the kinds of participants at one level of the independent variable are systematically different from those at the other level.
random assignment
The use of a random method (e.g. flipping a coin) to assign participants to different experimental groups.
matched groups
An experimental design technique in which participants who are similar on some measured variable are grouped into sets; the numbers of each matched set are then randomly assigned to different experimental conditions.
independent-groups design
An experimental design in which different groups of participants are assigned to different levels of the independent variable, such that each participant experiences only one level of the independent variable.
posttest-only design
An experiment using an independent-groups design in which participants are tested on the dependent variable only once.
pretest/posttest design
An experiment using an independent-groups design in which participants are tested on the key dependent variable twice: once before and once after exposure to the independent variable.
concurrent-measures design
An experiment using a within-groups design in which participants are exposed to all the levels of an independent variable at roughly the same time, and a single attitudinal or behavioral preference is the dependent variable.
repeated-measures design
An experiment using a within-groups design in which participants respond to a dependent variable more than once, after exposure to each level of the independent variable.
power
order effect
practice effect
carryover effect
counterbalancing
full counterbalancing
partial counterbalancing
Latin square
demand characteristic
manipulation check
pilot study
Which of these is not a drawback of a within-groups design?

Extraneous differences are held constant across conditions.
Participants cannot be returned to their original state after each condition.
Demand characteristics may result from hypothesis guessing with repeated testing.
Order effects can threaten internal validity.

Extraneous differences are held constant across conditions.
Which of these does not need to be considered as an alternative explanation of the results in a within-groups design experiment?

fatigue
selection
practice
boredom

selection
In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept for the mug. What is the independent variable in this experiment?

role of the participant
price that the buyer will pay
price that the seller will accept
name of the participant

role of the participant
What design is an experiment in which participants are randomly assigned to independent variable groups then tested on the dependent variable once?

within-groups
repeated measures
pretest/posttest
posttest only

posttest only
In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated measures design. How is the independent variable being manipulated in Tetiana’s design?

independent groups
within-groups
concurrently
as a participant variable

within-groups
In a word list-learning experiment, participants are given a list of words to study for 3 minutes and then, following a delay, are asked to recall the list. The length of time between the study period and the recall is being manipulated: it is 2 minutes, 5 minutes, or 10 minutes. Which of the following is a confounding variable?

All participants in the 2-minute condition are tested at 8:00a.m., those in the 5-minute condition are tested at noon, and those in the 10-minute condition are tested at 4:00 p.m.
The same list is used for each condition and is randomized for each participant.
The three groups are run simultaneously in three different rooms, and the room for each condition is randomly chosen before each group arrives.
Three different experimenters administer the task and rotate which condition they are administering.

All participants in the 2-minute condition are tested at 8:00a.m., those in the 5-minute condition are tested at noon, and those in the 10-minute condition are tested at 4:00 p.m.
Which of the following is not a method to interrogate construct validity in an experimental design?

pilot studies
checking for statistical significance
manipulation checks
adding additional conditions

checking for statistical significance
In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated measures design. What is the independent variable in this experiment?

depth perception
number of trials
disparity from perfect alignment
eye/eyes used

eye/eyes used
In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept. Which validity is concerned with applying the results to more expensive objects?

construct
internal
statistical
external

external
Which of these is not an advantage of within-groups designs?

elimination of practice effects
assurance of equivalence of the groups
requirement of fewer participants
more statistical power

elimination of practice effects
In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept for the mug. How does Theo control for selection effects?

by using a control group
by using matched-groups design
by random assignment of participants
by using a pretest/posttest design

by random assignment of participants
What does use of a Latin square assure with regard to conditions in a within-groups experiment?

that each participant will have a unique order of the conditions
that the order of the conditions will be randomized for each group
that each condition appears in each position within the order at least once
that all possible orders of conditions will be used

that each condition appears in each position within the order at least once
In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated measures design. She plans to have 60 participants and to use full counterbalancing. How many participants will be in each group?

six
ten
twenty
thirty

ten
In a word list-learning experiment, participants are given a list of words to study for 3 minutes and then, following a delay, are asked to recall the list. The length of time between the study period and the recall is being manipulated: it is 2 minutes, 5 minutes, or 10 minutes. Since different groups need different amounts of time, the first 25 participants who arrive are assigned to the 10-minute group, the next 25 are assigned to the 5-minute group, and the final 25 are assigned to the 2-minute group. What confound does this create?

demand characteristic
selection effect
experimenter bias
carryover effect

selection effect
What is a variable that the experimenter holds constant on purpose?

dependent
independent
control
confound

control
According to Cohen’s conventions for effect size, how do you describe an effect size when d = 0.50?

not existent
weak
moderate
strong

moderate
What type of group is a level of the independent variable that is intended to represent a neutral condition?

treatment
comparison
experimental
control

control
In a study of the span of apprehension, or how many objects you can assess (report seeing) after a brief exposure, the length of exposure is held constant and the number of objects is varied, from one to twelve. After a large number of trials, the percentage correct for each number of objects is found. What is the dependent variable in this experiment?

the percentage correct
the number of objects
the length of exposure
the number of trials

the percentage correct
In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated measures design. What is the dependent variable in this experiment?

distance out of alignment of the rods
how long the participant takes to complete the experiment
improvement in performance by the participant
eye/eyes used

distance out of alignment of the rods
In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept for the mug. What is the dependent variable in this experiment?

role of the participant
value selected for the mug
type of mug
name of the participant

value selected for the mug
In a study of the span of apprehension, or how many objects you can assess (report seeing) after a brief exposure, the length of exposure is held constant and the number of objects is varied, from one to twelve. After a large number of trials, the percentage correct for each number of objects is found. What is the independent variable?

the percentage correct
the number of objects
the length of exposure
the number of trials

the number of objects
In psychology lab, Tetiana is conducting an experiment on depth perception using the Howard-Dolman box. Inside the box are two vertical rods and a horizontal ruler. The participant manipulates the rods until they appear to be aligned at the same distance away, then the experimenter measures how far out of alignment they are. There are three conditions: left eye only, right eye only, and both eyes. Tetiana is using a repeated measures design. She finds that d = 1.53. What effect size is this?

weak
moderate
strong
This cannot be determined without knowing the number of participants.

strong
How many possible orders for full counterbalancing are there in a study with four conditions?

four
eight
sixteen
twenty-four

twenty-four
In a business class experiment on the endowment effect, Theo is comparing the value of a coffee mug to someone who owns it and is selling it to someone who is buying it. The endowment effect describes the tendency of sellers to value something they own more than buyers do. Participants are randomly assigned to be buyers or sellers of a mug with their first name on it. Buyers select the maximum price they would pay for the mug. Sellers select the minimum price they would accept. Which validity is concerned with the significance of the difference in the prices?

construct
internal
statistical
external

statistical
In what type of design does the experimenter sort the participants from lowest to highest of a relevant trait, form groups based on similar scores on that trait, then randomly assign those within each group to the different conditions?

independent groups
concurrent measures
matched-groups
within-groups

matched-groups