Deck 1: Describing Data With Graphs

Question 1

Which of the following choices best describes the methods dealt with by the branch of statistics called descriptive statistics?

A) organizing and summarizing data
B) quantifying and summarizing data
C) qualifying and quantifying data
D) qualifying and organizing data

Answer 1

A

Question 2

Which of the following terms refers to a graphical presentation of data that is displayed in order of descending magnitude?

A) a line chart
B) a stem-and-leaf plot
C) a relative frequency histogram
D) a Pareto chart

Answer 2

D

Question 3

In general, how do data distributions of incomes of employees in large firms tend to be shaped?

A) They are most often skewed to the right.
B) They are most often skewed to the left.
C) They are generally symmetric about the mean.
D) They are generally symmetric about the median.

Answer 3

A

Question 4

What does the sum of the frequencies for all classes always equal?

A) the number of classes
B) the class width
C) the total number of observations in the data set
D) one

Question 5

Which is the best type of chart for comparing two sets of qualitative data?

A) a line chart
B) a pie chart
C) a histogram
D) a bar chart

Question 6

Which of the following best describes the term "relative class frequency"?

A) It is the number of observations that fall into a given class in a frequency distribution.
B) It is the proportion of all observations that fall into a given class in a frequency distribution.
C) It is the difference between the numerical lower and upper limits of a class of quantitative data.
D) It is the average number of observations that fall into a given class in a frequency distribution.

Question 7

What are the characteristics of experimental units generally called?

A) data sets
B) descriptive statistics
C) internal data
D) variables

Question 8

Which of the following numbers constitutes the sum of the relative frequencies found in a relative frequency distribution for quantitative data?

A) 0
B) 1
C) 2
D) 3

Question 9

Suppose you have 180 observations divided into classes. One of the classes has a data class frequency of 36. Which of the following would be its relative class frequency?

A) 0.10
B) 0.18
C) 0.20
D) 0.36

Question 10

You asked ten of your classmates about their weight. On the basis of this information, you estimated that the average weight of all students at your school is 71.8 kilograms. What is this an example of?

A) descriptive statistics
B) statistical inference
C) a sample
D) a population

Question 11

What is the total area of the six bars in a relative frequency histogram for which the width of each bar is ten units?

A) 6
B) 10
C) 16
D) 60

Question 12

A politician who is running for office in a province with 3 million registered voters commissions a survey. In the survey, 5500 of the 10,000 registered voters interviewed say they plan to vote for her. Which of the following is the population of interest?

A) the 3 million registered voters in the province
B) the 10,000 registered voters interviewed
C) the 5500 voters interviewed who plan to vote for her
D) the 4500 voters interviewed who plan not to vote for her

Question 13

Which of the following is NOT a goal of descriptive statistics?

A) summarizing data
B) displaying aspects of the collected data
C) reporting numerical findings
D) estimating characteristics of populations

Question 14

What is a single observation about a specified characteristic of interest called?

A) a datum
B) an elementary unit
C) a sample
D) a univariate data set

Question 15

On what does the total area of the bars in a relative frequency histogram depend?

A) the sample size
B) the number of bars
C) the width of each bar
D) the population size

Question 16

Which of the following terms refers to the set of all possible observations about a specified characteristic of interest?

A) a frame
B) a multinomial data set
C) an observational study
D) a population

Question 17

What are the two graphical techniques most commonly used to present qualitative data?

A) bar chart and histogram
B) bar chart and pie chart
C) line chart and pie chart
D) line chart and histogram

Question 18

How is the relative frequency of a class computed?

A) by dividing the frequency of the class by the number of classes
B) by dividing the frequency of the class by the class width
C) by dividing the frequency of the class by the total number of observations in the data set
D) by dividing the frequency of the class by one less than the total number of observations in the data set

Question 19

Which of the following graphics is the most important and most commonly used graphical presentation of quantitative data?

A) the bar chart
B) the histogram
C) the pie chart
D) the dotplot

Question 20

A market share of 78.5% can be represented in a pie chart by a slice having a central angle measured in degrees. In this case, what would be the size of the central angle of the market share?

A) 39.3 degrees
B) 78.5 degrees
C) 141.3 degrees
D) 282.6 degrees

Question 21

In a sample of 1000 students in a university, 125, or 12.5%, are biology majors. The 12.5% is an example of statistical inference.

Question 22

If the manager of a grocery store wishes to display the sales trend, which of the following is the most effective type of graph to use?

A) a bar chart
B) a pie chart
C) a histogram
D) a line chart

Question 23

Persons or objects that have characteristics of interest to statisticians are called variables.

Question 24

A stem-and-leaf plot is used to display the distribution of which of the following kinds of data?

A) qualitative data
B) quantitative data
C) two quantitative variables
D) two qualitative variables

Question 25

A variable that is normally described in words, rather than numerically presented, is a qualitative variable.

Question 26

A variable is a characteristic that changes over time, and/or varies for different individuals or objects under consideration. An experimental unit is the individual or object on which a variable is measured.

Question 27

Suppose you are given a graphical portrayal of a relative frequency distribution of continuous quantitative data with the following characteristics. The lower and upper limits of the data classes are identified by tick marks on a horizontal axis. The corresponding relative class frequencies are represented by the areas of vertical rectangles connected to each other and positioned on top of each of these class intervals. What is such a graphical presentation called?

A) a stacked bar chart
B) a Pareto chart
C) a pictogram
D) a relative frequency histogram

Question 28

Individual observations within each class may be found in a frequency distribution.

Question 29

Which of the following should generally NOT be used when constructing a relative frequency histogram?

A) open-ended classes
B) equal-width classes
C) mutually exclusive classes
D) exhaustive classes

Question 30

How many classes should generally be used when constructing a relative frequency histogram?

A) between 1 and 5 classes
B) between 1 and 10 classes
C) between 5 and 12 classes
D) between 5 and 20 classes

Question 31

Statistical inference is the process of making an estimate, prediction, or decision about a population based on sample data.

Question 32

A qualitative variable about which observations can be made in only two categories is a bivariate data set.

Question 33

A branch of the statistics discipline that is used to develop and utilize techniques for properly making inferences about population characteristics based on information contained in a sample drawn from this population is called inferential statistics.

Question 34

Twenty-five percent of a sample of 200 professional tennis players indicated that their parents did not play tennis. This is an example of descriptive statistics, rather than inferential statistics.

Question 35

A histogram is a graphical device. What kind of data is it commonly used to display?

A) time series data
B) quantitative data
C) qualitative data
D) categorical data

Question 36

A local cable system using a sample of 1000 subscribers estimates that 50% of its subscribers watch premium channels at least five times per week. This is an example of inferential statistics, as opposed to descriptive statistics.

Question 37

In the term "frequency distribution," frequency refers to the number of data values or measurements falling within each class.

Question 38

Bar and pie charts are graphical techniques for qualitative data. The former focus the attention on the frequency of the occurrences of the categories; the latter emphasize the percentage of occurrences of each category.

Question 39

Which of the following might best be displayed using a bar chart?

A) time series data
B) continuous variables
C) qualitative variables
D) quantitative variables

Question 40

A branch of the statistics discipline that is used to develop and utilize techniques for effectively presenting numerical information is called inferential statistics.

Question 41

A pie chart is the familiar circular graph that shows how the measurements are distributed among the categories of a qualitative variable.

Question 42

A relative frequency distribution describes the proportion of the data values falling within each category.

Question 43

A bar chart in which the bars are ordered from smallest to largest is called a Pareto chart.

Question 44

A tabular summary of a categorical data set, which shows the number of observations that fall into each of several collectively exhaustive and mutually exclusive classes, is called a bar chart.

Question 45

In constructing a pie chart for a categorical variable, one sector of the pie is assigned to each category of the variable.

Question 46

A discrete quantitative variable is one that may assume values only at specific points on an interval of values, with inevitable gaps between them.

Question 47

The difference between a histogram and a bar chart is that the histogram represents quantitative data while the bar chart represents qualitative data.

Question 48

Multivariate data result when more than two variables are measured.

Question 49

Groupings of data created to enhance an understanding of them, usually by making the groups collectively exhaustive and mutually exclusive, are called classes or categories.

Question 50

A bar chart for a categorical variable shows the same distribution of measurements in categories as the pie chart, except that the height of each bar measures how often a particular category was observed.

Question 51

A relative frequency distribution describes the proportion of the data values falling within each class, and may be presented in a histogram form.

Question 52

Compared to the frequency distribution, the stem-and-leaf plot provides more detail, since it can describe the individual data values and show how many are in each group, or stem.

Question 53

Bivariate data result when fewer than two variables are measured on a single experimental unit.

Question 54

When constructing a frequency distribution for categorical data, it is always necessary to develop class boundaries.

Question 55

Suppose that the largest value in a set of data is 99, and the lowest value is 20. If the resulting frequency distribution is to have five classes of equal width, the class width should be 16.

Question 56

It is often a good idea to convert frequency distributions to relative frequency distributions when you compare two distributions with different amounts of data.

Question 57

A continuous quantitative variable is one that may assume values at all points on an interval of values, with no gaps between possible values.

Question 58

Persons or objects on which an experiment is performed are called experimental units.

Question 59

A relative frequency distribution is a tabular summary of a data set showing the proportions of all observations which fall into each of several collectively exhaustive and mutually exclusive classes.

Question 60

Univariate data result when a single variable is measured on a single experimental unit.

Question 61

A skewed histogram is one with a long tail extending either to the right or left.

Question 62

A histogram is said to be symmetric if, when we draw a vertical line down the centre of the histogram, the two sides are identical in shape and size.

Question 63

Stem-and-leaf plots are often used to analyze qualitative data in most real-life applications.

Question 64

If you wish to compare two data sets of different sizes, it is usually a good idea to convert frequency distributions to relative frequency distributions.

Question 65

A pie chart is a portrayal of divisions of some aggregate by a segmented circle in such a way that the sector areas are proportional to the sizes of the divisions in question.

Question 66

When a distribution has more values to the right and tails to the left, then it is considered to be skewed to the right.

Question 67

Bar charts can typically be formed with the bars vertical or horizontal without affecting the interpretation.

Question 68

The four classes: 0 to < 5, 5 to < 10, 10 to < 20, over 20, would be acceptable for developing a frequency distribution.

Question 69

If the six bars of a relative frequency histogram each have a width of five units, then the total area is 5.

Question 70

The class interval in a frequency distribution is the number of data values falling within each class.

Question 71

A relative frequency histogram can be constructed by letting either the horizontal axis or the vertical axis represent the variable of interest.

Question 72

When a distribution has more values to the left and tails to the right, then it is considered to be skewed to the left.

Question 73

When constructing a relative frequency distribution, if the data are discrete, it will always be necessary to develop class boundaries.

Question 74

A relative frequency histogram can be constructed for qualitative as well as quantitative data.

Question 75

One of the differences between a bar chart and a histogram is that a histogram typically displays data in a percentage form.

Question 76

For the same data, a relative frequency histogram will look exactly the same as a frequency histogram.

Question 77

Suppose you are given a stem-and-leaf plot that describes two-digit integers between 30 and 80. For one of the classes displayed, the row appears as 5|234. In this case, the numerical values being described are 25, 35, and 45.

Question 78

A dotplot is a graphical portrayal of an absolute or relative frequency distribution of continuous quantitative data having the following characteristics:
a. the lower and upper limits of the data classes are identified by tick marks on a horizontal axis, and
b. the corresponding absolute or relative class frequencies are represented by the areas of contiguous rectangles that stand on top of each of these class intervals.

Question 79

Relative frequency distributions are specifically constructed for analyzing discrete data.

Question 80

Time series data are often graphically depicted on a line chart. A line chart is a plot of the variable of interest over time.