$$\text{Class width} = \frac{\text{Largest data value} - \text{Smallest data value}}{\text{Number of classes}}$$

Question 1

Which of the following best describes a frequency distribution for qualitative data?

Accepted Answer

A table that lists each category of data and the number of occurrences for each category.

Question 2

Given the following frequency table for M&M colors, what is the relative frequency of yellow M&Ms?

Brown: 12, Yellow: 10, Red: 9, Orange: 6, Blue: 3, Green: 5

Accepted Answer

$$\frac{10}{45} \approx 0.2222$$

Question 3

Which of the following is NOT a characteristic of a bar graph for qualitative data?

Accepted Answer

The rectangles must touch each other.

Question 4

A Pareto chart is a special type of bar graph. What distinguishes a Pareto chart from a regular bar graph?

Accepted Answer

Bars are drawn in decreasing order of frequency or relative frequency.

Question 5

Why should relative frequencies be used instead of frequencies when comparing two data sets of different sizes using side-by-side bar graphs?

Accepted Answer

Relative frequencies account for differences in sample or population sizes, making comparisons fair.

Question 6

Which of the following best describes a pie chart?

Accepted Answer

A circle divided into sectors, with each sector proportional to the frequency of a category.

Question 7

When organizing continuous quantitative data into classes, what is the formula for determining class width?

Accepted Answer

$$	ext{Class width} = \frac{	ext{Largest data value} - 	ext{Smallest data value}}{	ext{Number of classes}}$$

Question 8

A histogram is constructed for continuous data. Which of the following statements is TRUE?

Accepted Answer

The rectangles touch each other, and the width of each rectangle represents a class interval.

Question 9

What is the main advantage of a stem-and-leaf plot over a histogram?

Accepted Answer

The raw data can be retrieved from the stem-and-leaf plot.

Question 10

Which of the following best describes a dot plot?

Accepted Answer

A plot where each observation is represented by a dot above its value on a number line.

Question 11

A distribution is described as 'skewed right.' Which of the following best describes its shape?

Accepted Answer

The tail to the right of the peak is longer than the tail to the left.

Question 12

Which of the following is the correct formula for the relative frequency of a category?

Accepted Answer

$$	ext{Relative frequency} = \frac{	ext{Frequency of the category}}{	ext{Sum of all frequencies}}$$

Question 13

A cumulative frequency distribution for continuous data displays:

Accepted Answer

The total number of observations less than or equal to the upper class limit of a class.

Question 14

Which of the following best describes a frequency polygon?

Accepted Answer

A graph that uses points connected by line segments to represent class frequencies at class midpoints.

Question 15

In a time-series plot, what is typically displayed on the horizontal axis?

Accepted Answer

Time at which the variable is measured.

Question 16

Suppose you are given the following data: 670, 675, 690, 705, 715, 725, 735. What is the class midpoint for the class 690–699?

Accepted Answer

$$\frac{690 + 699}{2} = 694.5$$

Question 17

Which of the following is TRUE about constructing frequency distributions for continuous data?

Accepted Answer

There is not one correct frequency distribution; some distributions better illustrate patterns than others.

Question 18

Which of the following graphs would be most appropriate for displaying the change in the Dow Jones Industrial Average from 1990 to 2007?

Accepted Answer

A time-series plot.

Question 19

If a histogram for a data set is bell-shaped, what does this indicate about the distribution?

Accepted Answer

The highest frequency occurs in the middle, and frequencies tail off to both sides symmetrically.

Question 20

Which of the following is a reason to use a split stem in a stem-and-leaf plot?

Accepted Answer

To better reveal the distribution when data are bunched within a few stems.

Organizing and Summarizing Data: Introductory Statistics Study Notes

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