# ch. 6 psych

The sample size depends on (2)
1. the type of study
2. the resources
The goal is to choose individuals for the sample who will ___________________
represent the behaviors and attitudes of the entire population.
____is the only technique for controlling for unknown extraneous variables.
Randomization
Random Selection insures that the sample selected is ________ of the population.
representative
_________ randomly distributes the extraneous variables over the treatment groups.
Random Assignment
Because random assignment is likely to create groups of different sizes, researchers often employ ___.
a. restricted random assignment
b. matched random assignment
c. simple random assignment
d. sampling
a. restricted random assignment
We will write a custom essay sample on
Any topic specifically for you
For only \$13.90/page
Sampling error:
difference in scores from the population to the sample.
Individuals are chosen at _____from the population such that the chance of any one individual being selected is known.
random
Probability samples are _______ of the population, so you should use these samples whenever it is feasible to do so.
most likely to be representative
Probability Samples (3)
1. Simple Random Samples
2. Cluster Samples
3. Stratified Random
Probability Samples: Simple Random Sample
All members have an equal chance of being selected.
Thus, if a population has 100 individuals, the chance of any one individual being selected for the sample is 1 in 100 or 1%.
Probability Samples: Cluster Sample
Individuals are chosen at random from groups within the population.
Cluster samples allow researchers to obtain a probability sample from a large population more easily than they would with a simple random sample, because the list from which individuals are selected is more manageable and easier to obtain.
Probability Samples: Stratified Random Sample
Individuals are chosen at random from the population such that the proportion of individuals with a particular characteristic is equivalent in the population and the sample.
Convenience Samples
-Individuals are chosen non-randomly from the population such that available individuals are chosen and the chance of any one individual being selected is not known.
-Samples drawn from that part of the population which is close to hand.
Convenience Samples ______the population
may not; More Sampling Error than Probability Sampling
Convenience Samples types (2)
1. Haphazard/Volunteer Samples
2. Quota Samples
Convenience Samples: Haphazard/Volunteer Samples
Individuals are chosen from the population such that available individuals are chosen.
______are quite common in psychological research.
Volunteer samples
Convenience Samples: Quota Samples
Individuals are chosen from the population (non-randomly) such that the proportion of individuals with a particular characteristic is equivalent in the population and the sample.
—Unlike a stratified random sample, the quota sample will make use of convenience sampling techniques such as recruiting participants from a participant sign-up pool or asking students sitting in the library to fill out the survey.
Which of the following statements is true about sampling plans?

a. A probability sampling plan is a better plan than a nonprobability one.
b. A sampling plan outlines strategies used to obtain a sample for a study.
c. Each study has its own sampling method, unique to that project.
d. Getting a sample that is the most representative is the ideal, not the goal, of the sampling plan.

b. A sampling plan outlines strategies used to obtain a sample for a study.
Apart from sample size, which of the following is typically not considered when determining the power of a study?

a. Sensitivity of the instruments used
b. Number of variables
c. Skill of the researcher
d. Data analysis techniques

c. Skill of the researcher
Sampling in research may be defined as:

A. identification of the population in which the researcher is interested.
B. selection of a subset of a population to represent the whole population.
C. ensurance that each person has a chance of being included in the study.
D. establishment of criteria for eligibility to participate in a study

B. selection of a subset of a population to represent the whole population.
A researcher was able to obtain a list of all lung cancer patients in the Southeast. If a table of random numbers was used to create a sample from that original list and then those individuals agreed to participate in a study, what kind of sample would have been created?

a. Cluster
b. Convenience
c. Simple random
d. Stratified random

c. Simple random
If every member of the population has an equal likelihood of being included in the study, the researcher has obtained a _________ sample.
a. cohort
b. random
c. convenience
d. demographic
b. random
A _________ is a subset of the ____________.
a. population; sample
b. population; random sample
c. sample; population
d. None of the above
c. sample; population
The complete set of individuals we wish to examine is called the _______
a. sample.
b. stratified sample.
c. random sample.
d. population.
d. population.
Another name for probability sampling is:

a. accidental sampling.
b. purposive sampling.
c. quota sampling.
d. random sampling.

d. random sampling.
The names of all the students in a class are listed on a separate pieces of paper. The teacher places the papers in a hat and mixes them thoroughly before reaching in to draw out five names. The teacher is using
a. simple random sampling
b. stratified random sampling
c. proportionate stratified random sampling
d. cluster sampling
a. simple random sampling
Which of the following is not required fora simple random sample from a population of 20 individuals?
A. Each individual in the population has a 1/20 probability of being selected.
B. The selection of one individual is independent of the selection of any other individual.
C. After 20 selections, each individual must have been selected exactly one time.
D. The individual obtained on any specific selection must be unpredictable.
C. After 20 selections, each individual must have been selected exactly one time.
A researcher is interested in the television viewing preferences of adolescent boys and selects a group of 25 boys to participate in a research study. The group of 25 boys is a _____
A. sample
B. statistic
C. population
D. parameter
A. sample
Once chosen, a score, event, or participant CANNOT be returned to the population to be selected again. This technique is referred to as
a. random sampling without replacement.
b. random sampling with replacement.
c. stratified random sampling.
d. convenience sampling.
a. random sampling without replacement.
Once chosen, a score, event, or participant CAN be returned to the population to be selected again. This technique is referred to as
a. random sampling without replacement.
b. random sampling with replacement.
c. stratified random sampling.
d. convenience sampling.
b. random sampling with replacement.
Which of the following is required in order to have a simple random sample?
a. Each individual is the population has an equal chance of being selected
b. The selection of one individual is independent of the selection of any other individual.
c. Each individual has an equal chance and the selections must be independent
d. You must use sampling with replacement
c. Each individual has an equal chance and the selections must be independent
A professor teaching an introductory psychology class of 200 obtains a sample of 25 students by electing every 8th name from the class list. The professor is using
a. simple random sampling
b. convenience sampling
c. proportionate stratified random sampling
d. systematic sampling
d. systematic sampling
Cluster sampling involves
A. randomly selecting individual subjects from a larger target population.
B. randomly selecting a naturally-occurring group of subjects from a larger target population.
C. randomly selecting several naturally occurring groups from a larger population, and then randomly selecting individuals from each group.
D. randomly selecting individuals from a larger target population and dividing subjects into groups on the basis of their status on a demographic variable
B. randomly selecting a naturally-occurring group of subjects from a larger target population.
Cluster sampling is:

a. a form of nonprobability sampling used in small surveys.
b. also known as multistage sampling.
c. unlikely to result in sampling errors.
d. useful when the target population is found in a small geographical area.

b. also known as multistage sampling.
A researcher would like to describe and compare the attitudes of four different ethnic groups of students at a local state college. To obtain participants for the study, the researcher should probably use _____.
a. simple random sampling
b. stratified random sampling
c. proportionate stratified random sampling
d. systematic sampling
b. stratified random sampling
A class consists of 20 girls and 12 boys. The names of all the students in the class are listed on separate pieces of paper. The teacher places all the boys’ names in one hat, all the girls’ name in another hat and mixes them thoroughly before reaching in to draw out five names from each hat. The teacher is using:
A. simple random sampling.
B. stratified random sampling.
C. proportionate stratified random sampling.
D. cluster sampling.
B. stratified random sampling.
In a study investigating nurses’ attitudes toward taking care of respiratory disease patients who had a long history of smoking, the researcher randomly selected a sample from a list of all the registered nurses from a randomly selected list of four states in the Southeast. If the researcher also selected the sample by randomly selecting nurses who smoke and those who do not, what sampling technique is being used?

a. Cluster
b. Quota
c. Stratified random
d. Systematic

c. Stratified random
In a study investigating nurses’ attitudes toward taking care of respiratory disease patients who had a long history of smoking, the researcher randomly selected a sample from a list of all the registered nurses from a randomly selected list of four states in the Southeast. If the researcher also selected the sample by randomly selecting nurses who smoke and those who do not, what sampling technique is being used?

a. Cluster
b. Quota
c. Stratified random
d. Systematic

c. Stratified random
Janice wishes to ensure that she has equal numbers of freshmen, sophomores, juniors, and seniors in her sample. She separates the population into subpopulations according to class rank and draws random samples from each subpopulation. Janice has engaged in ___________ sampling.
a. convenience
b. replacement
c. stratified random
d. non-random
c. stratified random
Which of the following sets of terms represents an appropriate pairing of a probability sampling method and a corresponding nonprobability sampling one?

a. Cluster sampling—snowball technique
b. Simple random sampling—convenience sampling
c. Stratified random sampling—quota sampling
d. Theoretical sampling—quota sampling

c. Stratified random sampling—quota sampling
Which of the following statements is true about stratified random sampling?

a. Allows the researcher to use a smaller sample size
b. Ensures obtaining a larger sample at lower cost
c. Internal validity is strengthened with this type of sampling
d. Involves the selection of certain subjects from a convenience sample

a. Allows the researcher to use a smaller sample size
If your primary concern is that the composition of your sample should accurately reflect the composition of the population, then you should use
a. parametric sampling
b. cluster sampling
c. stratified sampling
d. proportionate stratified sampling
d. proportionate stratified sampling
Findings of an intervention study with a convenience sample:

a. are generalizable to a wider group of patients with related problems.
b. are to be discounted because they are extremely biased.
c. provide no useful information.
d. should be replicated before being applied to a wider population.

d. should be replicated before being applied to a wider population.
A researcher obtains a sample of 25 participants by asking students in a introductory psychology class to sign up. The researcher is using
a. cluster sampling
b. quota sampling
c. simple random sampling
d. convenience sampling
d. convenience sampling
Which type of sampling will get the largest number of subjects in the shortest period of time?

a. Cluster sampling
b. Convenience sampling
c. Network or snowball sampling
d. Random sampling

b. Convenience sampling
Which of the following types of sampling is considered to be the weakest?

a. Cluster
b. Convenience
c. Quota
d. Systematic

b. Convenience
Which of the following samples is least likely to be representative of the overall population?

a. Convenience
b. Quota
c. Random
d. Stratified random

a. Convenience
You are shopping in the mall and are approached by individuals who identify themselves as researchers for a local food chain. They ask you to participate in their study by answering a few questions. As a subject for this survey, you were selected by which method of sampling?

A. Random sampling
B. Purposive sampling
C. Systematic sampling
D. Convenience sampling

D. Convenience sampling
The most commonly used sampling method in psychological research is probably
a. cluster sampling
b. quota sampling
c. simple random sampling
d. convenience sampling
d. convenience sampling
Which of the following is true about probability sampling?

A. It can take different forms, but random selection is always used.
B. Subjects are handpicked because they have the expertise to provide information for the study.
C. It guarantees that the sample is representative.
D. It is the most economical way to get large numbers of subjects.

A. It can take different forms, but random selection is always used.
What kind of sampling is used by a researcher who obtains a sample of preschool children by selecting individuals from a local daycare center?
A. simple random sampling
B. cluster sampling
C. probability sampling
D. nonprobability sampling
D. nonprobability sampling
A major advantage of using a questionnaire for data collection is that a questionnaire:

A. allows for follow-up on subject’s responses.
B. eliminates all sources of bias in subject’s responses
C. can be distributed to large samples.
D. is easy to construct.

C. can be distributed to large samples.
The population from which the researcher selects the actual study sample is referred to as:

A. target population.
B. theoretical population.
C. accessible population.
D. scientific population.

C. accessible population.
Which of the following is an example of purposive sampling?

A. Volunteers are solicited from the entire population, and those who agree become subjects in the study.
B. Subjects who have knowledge about the study topic are asked to participate in the study; those who agree become the sample.
C. Sample members are determined by finding a designated number of subjects from each of several identified groups (men, women, high school graduates, etc.).
D. The names of all possible subjects are put into a hat, and an adequate number are drawn out.

B. Subjects who have knowledge about the study topic are asked to participate in the study; those who agree become the sample.
In which type of research is there high researcher control, random sampling, and laboratory setting?
A.Descriptive
B.Correlational
C.Quasiexperimental
D.Experimental
D.Experimental
A researcher designs a study that uses a random sampling method to decrease the likelihood of bias in the study sample. This strategy was used to implement:
A.manipulation
B.control
C.data collection
D.experimental research
B.control
Feasibility is determined by examining which of the following?
A.Researcher’s credibility
B.Significance of research problem
C.Availability of subjects
D.Previous studies
C.Availability of subjects
In a research proposal, the investigator notes that written permission has been obtained from three local hospitals to access patients for the proposed study. This is an example of what aspect of a study?
A.Reliability
B.Methodology
C.Ethics
D.Feasibility
D.Feasibility
Sampling in research may be defined as:
a. insurance that each person has a chance of being included in the study.
b. establishment of criteria for eligibility to participate in a study.
c. identification of the population in which the researcher is interested.
d. selection of a subset of a population to represent the whole population.
d. selection of a subset of a population to represent the whole population.
A researcher is interested in studying lifestyle management in patients with inflammatory bowel disease. The researcher contacts the Crohn’s and Colitis Foundation of America to determine how to best access this patient population. Patients with inflammatory bowel disease are an example of which of the following?

a. Accessible population
b. Element
c. Sample
d. Target population

d. Target population
Which is the largest group from among this list?

a. Accessible population
b. Control group
c. Sample
d. Target population

d. Target population
Sample attrition would be reflected by the:

a. average death rate of the population under study.
b. inability to access identified members of a population.
c. number of patients who die while participating in a study.
d. number of patients who drop out of a study

d. number of patients who drop out of a study
The sample size needed for a study increases when:

a. the alpha level is increased from .01 to .05.
b. the number of variables in the study increases.
c. a one-tailed versus a two-tailed statistical test is used.
d. the sensitivity of the instruments used is high.

b. the number of variables in the study increases.
Which of the following is true about sample size?

a. An adequate sample size is particularly important to detect differences when they do in fact exist.
b. Evaluating the possibility of a Type I error will help determine sample size.
c. Finding a significant difference in study groups occurs most often with smaller samples.
d. Sample size is especially important to support significant findings.

a. An adequate sample size is particularly important to detect differences when they do in fact exist.
A researcher reports on a study conducted to determine if a new educational program has helped dialysis patients become more compliant with their fluid restrictions. The findings indicated that there was no difference. The report did include that a power analysis was performed to determine if the sample size (n = 100) was adequate. The power level was .5. What should the reader conclude?

a. A sample of 100 is certainly adequate in a clinical study. The researcher should adjust the educational program.
b. Chances are high that a Type I error has occurred.
c. Findings of no difference are not surprising; it is difficult to make an impact on this population of patients.
d. There is a high likelihood that the sample size was not adequate, and the study should be replicated using more subjects.

d. There is a high likelihood that the sample size was not adequate, and the study should be replicated using more subjects.
To detect a significant difference between two groups when the effect size is small, what should the researcher do?

a. Conduct a pilot study.
b. Obtain a different sample.
c. Increase the sample size.

c. Increase the sample size.
The term “comparison group” in research refers to the group of patients in a:

a. nonrandom sample who do not receive a treatment.
b. nonrandom sample who receive a treatment.
c. random sample who do not receive a treatment.
d. random sample who receive a treatment.

a. nonrandom sample who do not receive a treatment.
A researcher wants to obtain a sample of individuals who are HIV positive. Which of the following sampling methods would be the most effective way to obtain a sample?

a. Accidental sampling
b. Cluster sampling
c. Network sampling
d. Simple random sampling

c. Network sampling
Which of the following is true about network sampling?

a. Eligibility criteria do not need to be defined carefully.
b. Finding large numbers of subjects by this means is easy and economical.
c. Sample representativeness is guaranteed by using this technique.
d. Subjects who have knowledge of a situation, often sensitive or not socially acceptable, are identified by others in the same type of situation.

d. Subjects who have knowledge of a situation, often sensitive or not socially acceptable, are identified by others in the same type of situation.
In a study investigating nurses’ attitudes toward taking care of respiratory disease patients who had a long history of smoking, the researcher randomly selected a sample from a list of all the registered nurses from a randomly selected list of four states in the Southeast. Because the sample was drawn randomly, to what population can the findings of the study be generalized? Registered nurses in the:

a. Selected four states
b. Southeast
c. Southeast who are actively working
d. United States

b. Southeast
The “pseudopatients” who were admitted to mental hospitals in Rosenhan’s -1973- study were:
A. all discharged from the hospitals within72 hours due to their “remission”
B. identified by hospital staff as being “normal” during the second week of their stay
C. identified by other patients but not staff members as being “normal”
D. identified by staff members as being “normal” only after they stopped feigning symptoms
C. identified by other patients but not staff members as being “normal”
A researcher is interested in the eating behavior of rats and selects a group of 25 rats to be tested in a research study. The group of 25 rats is a __________.
a. sample
b. statistic
c. population
d. parameter
a. sample
A researcher is interested in the effect of St. Johns Wort on memory. A group of 25 college students is selected to participate in a research study. The average memory score obtained for the 25 students is a __________.
a. sample
b. statistic
c. population
d. parameter
b. statistic
A researcher is curious about the average IQ of registered voters in the state of Florida. The entire group of registered voters in Florida is an example of a __________.
a. sample
b. statistic
c. population
d. parameter
c. population
A researcher is curious about the average IQ of registered voters in the state of Florida. If this average could be obtained, it would be an example of a __________.
a. sample
b. statistic
c. population
d. parameter
d. parameter
Although research questions typically concern a ________, a research study typically examines a __________.
a. sample, population
b. statistic, sample
c. population, sample
d. parameter, population
c. population, sample
Statistical techniques that summarize, organize, and simplify data are classified as __________.
a. population statistics
b. sample statistics
c. descriptive statistics
d. inferential statistics
c. descriptive statistics
A characteristic, usually a numerical value, that describes an entire population of scores is a __________.
a. parameter
b. statistic
c. variable
d. constant
a. parameter
The average score for an entire population would be an example of a __________.
a. parameter
b. statistic
c. variable
d. constant
a. parameter
Which of the following is a good strategy to increase the representativeness of a sample?
a. Use random sampling without replacement. b. Use convenience sampling.
c. Decrease the sample size.
d. Increase the sample size.
d. Increase the sample size.
Madeleine has developed a new scale to measure conscientiousness. This scale would best be described as a(n)
a. achievement test.
b. personality inventory.
c. aptitude test.
d. stratified test.
b. personality inventory.
Researchers give a test to participants on two separate occasions in order to assess
a. concurrent validity.
b. criterion validity.
c. split-half reliability.
d. test-retest reliability.
d. test-retest reliability.
Latoya develops a new scale to measure beliefs in extraterrestrials. She gives her new scale to 100 people twice, two months apart. She finds that in general, people who believe in extraterrestrials at Time 1 also believe in extraterrestrials at Time 2. Latoya’s scale exhibits good
a. concurrent validity.
b. content validity.
c. test-retest reliability.
d. split-half reliability.
c. test-retest reliability.
Veronica intended to develop a test to measure locus of control, but it actually measures self-esteem. Veronica’s test has low
a. test-retest reliability.
b. validity.
c. interrater reliability.
d. split-half reliability.
b. validity.
__________ refers to the extent to which a test exhibits consistency.
a. Concurrent validity
b. Criterion validity
c. Content validity
d. Reliability
d. Reliability
________ validity refers to the degree to which the score on a test corresponds with another measure of the designated trait.
a. Criterion
b. Concurrent
c. Content
d. Split-half
b. Concurrent
Kimberly’s new depression scale correlates positively with psychologists’ ratings of their patients’ depression. Kimberly’s depression scale shows high
a. criterion validity.
b. concurrent validity.
c. split-half reliability.
d. interrater reliability.
b. concurrent validity.
_________ validity is established by comparing the score on a test with a future score on another test.
a. Criterion
b. Concurrent
c. Content
d. Split-half
a. Criterion
Researchers have found that SAT scores predict first-semester grade point average. This demonstrates _________ validity.
a. criterion
b. concurrent
c. content
d. split-half
a. criterion
Researchers often use a panel of judges to assess the _______ validity of their test items.
a. criterion
b. concurrent
c. content
d. split-half
c. content
All of the following are disadvantages of telephone interviews EXCEPT:
a. Many people screen or block calls from people whom they do not know.
b. The researcher is more likely to obtain a biased sample using a telephone
survey than a mail survey.
c. The researcher cannot examine nonverbal behavior of the respondent.
d. It is more difficult to establish rapport over the telephone than in personal
interviews.
b. The researcher is more likely to obtain a biased sample using a telephone
survey than a mail survey.
Dale wants to ensure that he has a high response rate for his survey. Which method would be best?
a. Mail survey
b. Personal interview
c. Telephone interview
d. Demographic interview
b. Personal interview
Which of the following is one of the guidelines for writing good survey questions?
a. Questions should use familiar vocabulary.
b. Questions should be lengthy so that participants will be able to understand
them better.
c. Questions should be above the reading level of the individuals you intend
to test.
d. All of the above.
a. Questions should use familiar vocabulary.
Bess conducts a study in which she measures self-esteem and grade point average in a sample of 50 college students. She hypothesizes that higher self-esteem will be associated with higher grade point average. This research approach is best described as _________ research.
a. archival
b. correlational
c. grounded theory
d. ethnographic
b. correlational
If there is a ______ correlation, then the two variables are not related.
a. positive
b. negative
c. zero
d. curvilinear
c. zero
Researchers use correlations to
a. understand cause-and-effect relationships.
b. make predictions.
c. understand the axial coding process.
d. All of the above.
b. make predictions.