Bstat chapter 2

A stem-and-leaf display is a graphical portrayal of a data set that shows the data set’s overall pattern of
variation.
true
The relative frequency is the frequency of a class divided by the total number of measurements.
true
A bar chart is a graphic that can be used to depict qualitative data
true
Stem-and-leaf displays and dot plots are useful for detecting outliers.
true
A scatter plot can be used to identify outliers.
false
When looking at the shape of the distribution using a stem-and-leaf, a distribution is skewed to the
right when the left tail is shorter than the right tail.
true
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When we wish to summarize the proportion (or fraction) of items in a class we use the frequency
distribution for each class.
false
When establishing the classes for a frequency table it is generally agreed that the more classes you use
the better your frequency table will be.
false
The sample cumulative distribution function is non-decreasing.
true
A frequency table includes row and column percentages.
false
A(n) ______ is a graph of a cumulative distribution.
Ogive plot
________ can be used to study the relationship between two variables.
Crosstabulation tables
Row or column percentages can be found in:
Crosstabulation tables
All of the following are used to describe quantitative data except the
pie chart
An observation separated from the rest of the data is a(n)
outlier
Which of the following graphs is for qualitative data?
Bar Chart
A Stem and Leaf display is best used to
Display the shape of the distribution.
When grouping a large sample of items into classes, the ______________ is a better tool than the
___________.
Histogram, stem and leaf display
A ______________ displays the frequency of each group with qualitative data and a ____________
displays the frequency of each group with quantitative data.
Bar chart, histogram
A ______________ shows the relationship between two variables
Scatter Plot
A ______________ can be used to differentiate the “vital few” causes of quality problems from
the “trivial many” causes of quality problems.
Pareto chart
______________ and _____________ are used to describe qualitative (categorical) data.
Bar charts, pie charts
Which one of the following statistical tools is used with quantitative data?
Histogram
When developing a frequency distribution the class (group), intervals should be
mutually exclusive.
Which of the following graphical tools is not used to study the shapes of distributions?
Scatter plot
All of the following are used to describe qualitative data except the:
Histogram
If there are 130 values in a data set, how many classes should be created for a frequency histogram?
8
If there are 120 values in a data set, how many classes should be created for a frequency histogram?
7
If there are 62 values in a data set, how many classes should be created for a frequency histogram?
6
If there are 30 values in a data set, how many classes should be created for a frequency histogram?
5
A CFO is looking at how much of a company’s resources are spent on computing. He
samples companies in the pharmaceutical industry and developed the following stem-and-leaf
Skewed to the right
A CFO is looking at how much of a company’s resources are spent on computing. He
samples companies in the pharmaceutical industry and developed the following stem-and-leaf
5.2
A CFO is looking at how much of a company’s resources are spent on computing. He
samples companies in the pharmaceutical industry and developed the following stem-and-leaf
If a frequency histogram were to be created using these data, how many classes would you create?
6
A CFO is looking at how much of a company’s resources are spent on computing. He
samples companies in the pharmaceutical industry and developed the following stem-and-leaf
What would be the class length that would be used in creating a frequency histogram?
1.4
A CFO is looking at how much of a company’s resources are spent on computing. He
samples companies in the pharmaceutical industry and developed the following stem-and-leaf
5.2 – 6.4
The US local airport keeps track of the percentage of flights arriving within 15 minutes of their
scheduled arrivals. The stem-and-leaf plot of the data for one year is below:

How many flights were used in this plo

12
The US local airport keeps track of the percentage of flights arriving within 15 minutes of their
scheduled arrivals. The stem-and-leaf plot of the data for one year is below:

In developing a histogram of these data, how many classes would be used?

4
The US local airport keeps track of the percentage of flights arriving within 15 minutes of their
scheduled arrivals. The stem-and-leaf plot of the data for one year is below:

What would be the class length for creating the frequency histogram?

1.7
A company collected the ages from a random sample of its middle managers with the resulting
frequency distribution shown below:

What would be the approximate shape of the relative frequency histogram?

Skewed to the left
A company collected the ages from a random sample of its middle managers with the resulting
frequency distribution shown below:

What is the relative frequency for the largest interval?

.283
A company collected the ages from a random sample of its middle managers with the resulting
frequency distribution shown below:

What is the midpoint of the third class interval?

32.5
The 550 students answered an additional question with the following results based on their rating of
their instructor:

What proportion of the students who rated their instructor as very or somewhat effective received a B
or better in the class?

0.898
The 550 students answered an additional question with the following results based on their rating of
their instructor:

What proportion of all 550 students received less than a C?

0.08
822 customers were randomly selected from those who had recently bought a book over
the internet. The chart below shows the breakdown of the classification of the book
What percentage of the books purchased were either mystery or science fiction/fantasy?
36.5
822 customers were randomly selected from those who had recently bought a book over
the internet. The chart below shows the breakdown of the classification of the book
type:

What percentage of the books purchased were self-help books?

11.44%
822 customers were randomly selected from those who had recently bought a book over
the internet. The chart below shows the breakdown of the classification of the book
type:

What percentages of books were in the top two categories?

43.43
A graphical display of categorical data made up of vertical or horizontal bars is called a _____.
bar chart
A flaw possessed by a population or sample unit is _____
defect
A graphical portrayal of a data set that divides the data into classes and gives the frequency of each
class is a(n) _____.
Histogram
The number of measurements falling within a class interval is called the _____
Frequency
A relative frequency curve having a long tail to the right is said to be _____.
Skewed to the right
The percentage of measurements in a class is called the _____ of that class
relative frequency
A histogram that tails out towards larger values is _____
skewed to the right
A histogram that tails out towards smaller values is _____
skewed to left
A(n) ___________ is a graphical display of categorical data made up of vertical or horizontal
bars.
bar chart
A __________ can be used to differential the “vital few” causes of quality problems from the “trivial
many” causes of quality problems.
Pareto chart
A ________ is a graph of cumulative distribution.
Ogive plot
Using the following data, describe the shape of the data
distribution
skewed to rightt
Using the following data, what would be the range of the values of the stem in a stem and leaf
display?
11-18
Using the following data, what would be the leaf unit in a stem and leaf display?
10
Consider the following data on distances traveled by people to visit the local amusement park and
calculate the relative frequency for the shortest distance.
.375
Consider the following data on distances traveled by people to visit the local amusement park and
calculate the relative frequency for the distances over 24 miles
.150
The following is a partial relative frequency distribution of grades in an introductory statistics
course.

Find the relative frequency for B grade

.37
The following is a relative frequency distribution of grades in an introductory statistics
course.

If this was the distribution of 200 students, find the frequency for the highest two grades:

118
The following is a relative frequency distribution of grades in an introductory statistics
course.

If this was the distribution of 200 students, find the frequency of failures

12
The following is a relative frequency distribution of grades in an introductory statistics
course.

If we wish to depict these data using a pie chart, find how many degrees should be assigned to the
highest grade of A.

79.2
Recently an advertising company called 200 people and asked to identify the
company that was in an ad running nationwide. The following results were
obtained:

What percentage of those surveyed were female and could not recall the company?

22.0%
Recently an advertising company called 200 people and asked to identify the
company that was in an ad running nationwide. The following results were
obtained:

What percentage of those surveyed could not correctly recall the company?

58.00%
The local electronics retailer has recently conducted a study on purchasers of
large screen televisions. The study recorded the type of television and the credit
account balance of the customer at the time of purchase. The following results were
obtained:

What percentage of purchases were Plasma televisions by customers with the smallest credit balances?

19.6%
The local electronics retailer has recently conducted a study on purchasers of
large screen televisions. The study recorded the type of television and the credit
account balance of the customer at the time of purchase. The following results were
obtained:

What percentage of the customers with the highest credit balances purchased an LCD television?

5.9%
The number of weekly sales calls by a sample of 25 pharmaceutical salespersons is below:

24, 56, 43, 35, 37, 27, 29, 44, 34, 28, 33, 28, 46, 31, 38, 41, 48, 38, 27, 29, 37, 33, 31, 40, 50

How many classes should be used in the construction of a histogram?

5
The number of weekly sales calls by a sample of 25 pharmaceutical salespersons is below:

24, 56, 43, 35, 37, 27, 29, 44, 34, 28, 33, 28, 46, 31, 38, 41, 48, 38, 27, 29, 37, 33, 31, 40, 50

What is the shape of the distribution of the data?

skewed right
The number of items rejected daily by a manufacturer because of defects for the last 30 days are: 20,
21, 8, 17, 22, 19, 18, 19, 14, 17, 11, 6, 21, 25, 4, 19, 9, 12, 16, 16, 10, 28, 24, 6, 21, 20, 25, 5, 17, 8

How many classes should be used in the construction of a histogram?

5