Deck 2: Graphical and Tabular Descriptive Techniques

Question 1

Interval data, such as heights, weights, and incomes, are also referred to as quantitative or numerical data.

Answer 1

True

Question 2

All calculations are permitted on interval data.

Answer 2

True

Question 3

You cannot calculate and interpret differences between numbers assigned to nominal data.

Answer 3

True

Question 4

A relative frequency distribution lists the categories and their counts.

Question 5

The intervals (classes) in a histogram do not overlap.

Question 6

Your age group (1-9; 10-19; 20-29; 30-39; etc.) is an interval variable.

Question 7

The values of quantitative data are categories.

Question 8

Whether or not you are over the age of 21 is a nominal variable.

Question 9

From a pie chart you are able to find the frequency for each category.

Question 10

One of the advantages of a pie chart is that it clearly shows that the total percentages of all the categories add to 100%.

Question 11

A bar chart is used to represent interval data.

Question 12

Nominal data are also called qualitative or categorical data.

Question 13

Your age is an interval variable.

Question 14

With nominal data, there is one and only one way the possible values can be ordered.

Question 15

Interval data may be treated as ordinal or nominal.

Question 16

Your gender is a nominal variable.

Question 17

A frequency distribution lists the categories and the proportion with which each occurs.

Question 18

Your final grade in a course (A, B, C, D, E) is a nominal variable.

Question 19

A variable is some characteristic of a population or sample.

Question 20

Bar and pie charts are graphical techniques for nominal data. The former focus the attention on the frequency of the occurrences of each category, and the later emphasizes the proportion of occurrences of each category.

Question 21

A histogram is said to be symmetric if, when we draw a vertical line down the center of the histogram the two sides are nearly identical.

Question 22

When a distribution has more values to the right and tails to the left, we say it is skewed negatively.

Question 23

According to the stem-and-leaf plot below, this data set is symmetric.

Question 24

A stem-and-leaf display represents nominal data.

Question 25

According to the stem-and-leaf plot below, the median quiz score for this data set is 8.

Question 26

The original observations cannot be determined once they are grouped into a frequency distribution.

Question 27

In a histogram, each observation is assigned to one or more classes.

Question 28

The number of observations within each class may be found in a frequency distribution.

Question 29

The advantage of a stem-and-leaf display over a histogram is that we can see the actual observations.

Question 30

When a distribution has more values to the left and tails off to the right, it is skewed negatively.

Question 31

According to the stem-and-leaf plot below, this data set has a negative median.

Question 32

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

Question 33

The sum of cumulative relative frequencies always equals 1.

Question 34

A cumulative relative frequency distribution lists the number of observations that lie below each of the class limits.

Question 35

A stem-and-leaf display reveals more information about the original data than does a histogram.

Question 36

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

Question 37

The intervals (classes) in a histogram are equally wide.

Question 38

The number of class intervals in a histogram depends on the number of observations in the data set.

Question 39

A histogram represents interval data.

Question 40

The sum of relative frequencies in a distribution always equals 1.

Question 41

A line chart is created by plotting the values of the variable on the vertical axis and the time periods on the horizontal axis.

Question 42

Data for calories and salt content (milligrams of sodium) in 17 brands of meat hot dogs are shown in the scatter diagram below. According to this diagram, it appears that hot dogs that are high in sodium are generally low in calories, and hot dogs with low sodium are generally high in calories.

Question 43

The line chart below shows cucumber prices fluctuated from $2.00 per pound to over $4.50 per pound during the year.

Question 44

The graph below represents a line graph.

Question 45

Experience shows that few students hand in their statistics exams early; most prefer to hand them in near the end of the test period. This means the time taken by students to write exams is positively skewed.

Question 46

The two most important characteristics revealed by the scatter diagram are the strength and direction of the linear relationship.

Question 47

The scatter diagram below depicts data with a negative linear relationship.

Question 48

Correlation implies causation.

Question 49

When two variables are linearly related, and tend to move in opposite directions, we describe the nature of their association as a negative linear relationship.

Question 50

The graph below is an example of a histogram.

Question 51

A modal class is the class with the largest number of observations.

Question 52

The sum of cumulative relative frequencies always equals 1.

Question 53

The line chart below shows tomato prices each month from January (month 1) to December last year ($ per pound). By looking at this chart you can see the lowest tomato prices occurred in July.

Question 54

If two variables have a strong linear relationship, that means one variable is causing the other variable to go up or down.

Question 55

The graphical technique used to describe the relationship between two interval variables is the scatter diagram.

Question 56

The two most important characteristics to examine in a scatter diagram are the number of possible categories for X and Y and the number of observations in each category.

Question 57

The first scatter diagram below shows a stronger linear relationship than the second scatter diagram. (Assume the scales on both scatter diagrams are the same.)

Question 58

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

Question 59

If we draw a straight line through the points in a scatter diagram and most of the points fall close to the line, there must be a positive relationship between the two variables.

Question 60

A line chart that is flat shows no fluctuation in the variable being presented.

Question 61

For what type of data are frequencies the only calculations that can be done?

A) Interval data
B) Nominal data
C) Ordinal data
D) None of these choices.

Question 62

Which of the following represents a graphical presentation of interval data?

A) A bar chart.
B) A histogram.
C) A pie chart.
D) All of these choices are true.

Question 63

The relative frequency of a class in a histogram is computed by

A) dividing the frequency of the class by the number of classes.
B) dividing the frequency of the class by the class width.
C) dividing the frequency of the class by the total of all frequencies.
D) None of these choices.

Question 64

The classification of student major (accounting, economics, management, marketing, other) is an example of a(n)

A) nominal random variable.
B) interval random variable.
C) continuous random variable.
D) parameter.

Question 65

A researcher wishes to estimate the textbook costs of first-year students at Barry University. To do so, he recorded the textbook cost of 300 first-year students and found that their average textbook cost was $195 per semester. The variable of interest to the researcher is

A) textbook cost.
B) class rank.
C) number of students.
D) name of university.

Question 66

Which of the following statements about pie charts is false?

A) A pie chart is a graphical representation of a relative frequency distribution.
B) You can always determine frequencies for each category by looking at a pie chart.
C) The total percentage of all the slices of a pie chart is 100%.
D) The area of a slice of a pie chart is the proportion of all the individuals that fall into that particular category.

Question 67

Which of the following situations is best suited for a pie chart?

A) The number of dollars spent this year on each type of legal gambling.
B) The percentage of a charitable donation that goes to administrative costs vs. directly to the charity.
C) The number of students in your class who received an A, B, C, D, F on their exam.
D) All of these choices are true.

Question 68

Suppose you measure the number of minutes it takes an employee to complete a task, where the maximum allowed time is 5 minutes, and each time is rounded to the nearest minute. Data from 130 employees is summarized below. How long did it take most employees to complete the task?

A) 5 minutes
B) 3 minutes
C) 30 minutes
D) 50 minutes

Question 69

For which type of data are the values arbitrary numbers?

A) Interval data
B) Nominal data
C) Ordinal data
D) None of these choices.

Question 70

Compare the two histograms below. Which statement is true?

A) The spread of histogram A is smaller than the spread of histogram B.
B) The spread of histogram A is larger than the spread of histogram B.
C) The spread of histogram A is the same as the spread of histogram B.
D) You cannot compare the spreads of these two histograms without the original data.

Question 71

Which situation identifies when to use pie charts and/or bar charts?

A) You want to describe a single set of data.
B) Your data is nominal.
C) You want to show the number or the percentage of individuals in each category.
D) All of these choices are true.

Question 72

Which of the following statements about histograms is false?

A) The intervals of a histogram do not overlap.
B) Every observation is assigned to one and only one class in a histogram.
C) The intervals of a histogram are equally wide.
D) None of these choices.

Question 73

Which of the following describes the shape of the histogram below?

A) Positively skewed
B) Negatively skewed
C) Symmetric
D) None of these choices

Question 74

All calculations are permitted on what type of data?

A) Interval data
B) Nominal data
C) Ordinal data
D) All of these choices are true.

Question 75

A professor examines the relationship between minutes studying and exam score (out of 200 points) for a random sample of his students. The scatter diagram is shown below. It appears that study time has somewhat of a positive linear relationship with exam score.

Question 76

Car buyers were asked to indicate the car dealer they believed offered the best overall service. The four choices were Convoy Motors (C), Mako Chrysler (M), Torrent Auto (T), and Unequaled Chevrolet (U). The following data were obtained: What percentage of car buyers identified Convoy Motors as having the best overall service?

A) 1/4 = 0.25 or 25%
B) 14/40 = 0.35 or 35%
C) 14%
D) None of these choices.

Question 77

The classification of student class designation (freshman, sophomore, junior, senior) is an example of a(n)

A) nominal random variable.
B) interval random variable.
C) ordinal random variable.
D) a parameter.

Question 78

Compare the two histograms below. Which statement is true?

A) The center of histogram A is lower than the center of histogram B.
B) The center of histogram A is higher than the center of histogram B.
C) The center of histogram A is the same as the center of histogram B.
D) You cannot compare the centers of these two histograms without the original data.

Question 79

Values must represent ordered rankings for what type of data?

A) Interval data
B) Nominal data
C) Ordinal data
D) None of these choices.

Question 80

Which of the following statements about histograms is false?

A) A histogram is a summary of interval data.
B) A histogram is made of a series of intervals, called classes.
C) The classes in a histogram cover the complete range of observations.
D) All of these choices are true.