Question 1

Which of the following best describes a frequency distribution?

Accepted Answer

A table that shows classes or intervals of data with a count of the number of entries in each class.

Question 2

Given a data set with a minimum value of 120 and a maximum value of 340, and you want to create 8 classes, what is the appropriate class width?

Accepted Answer

$$\frac{340 - 120}{8} = 27.5$$, so round up to 28

Question 3

What is the cumulative frequency for the third class if the frequencies for the first three classes are 5, 8, and 12?

Accepted Answer

$$5 + 8 + 12 = 25$$

Question 4

Which of the following is NOT a characteristic of a frequency histogram?

Accepted Answer

Bars are separated by gaps to show class boundaries.

Question 5

How do you calculate the midpoint of a class with lower class limit 150 and upper class limit 185?

Accepted Answer

$$\frac{150 + 185}{2} = 167.5$$

Question 6

A relative frequency histogram differs from a frequency histogram in that:

Accepted Answer

The vertical axis measures relative frequencies instead of actual frequencies.

Question 7

If a class has a frequency of 7 in a data set of 35 values, what is the relative frequency of that class?

Accepted Answer

$$\frac{7}{35} = 0.2$$

Question 8

Which of the following best describes an ogive?

Accepted Answer

A line graph that displays the cumulative frequency of each class at its upper class boundary.

Question 9

Why is it important to round up the class width when constructing a frequency distribution?

Accepted Answer

To ensure all data values are included in the classes without overlap.

Question 10

A researcher collects the following screen times (in minutes) for 5 adults: 120, 150, 180, 210, 240. What is the range of this data set?

Accepted Answer

$$240 - 120 = 120$$

Question 11

Which of the following statements about class boundaries is correct?

Accepted Answer

Class boundaries are the numbers that separate classes without forming gaps between them.

Question 12

If the cumulative frequency for the fourth class is 22 and the frequency for the fifth class is 7, what is the cumulative frequency for the fifth class?

Accepted Answer

$$22 + 7 = 29$$

Question 13

Which graph would you use to best visualize the percentage of adults with screen times in different intervals?

Accepted Answer

Relative frequency histogram

Question 14

A frequency polygon is constructed by plotting which of the following?

Accepted Answer

Class midpoints and their corresponding frequencies

Question 15

If a frequency distribution has 6 classes and the range of the data is 90, what is the minimum class width you should use?

Accepted Answer

$$\frac{90}{6} = 15$$, so round up to 15

Question 16

Which of the following is a correct step in constructing a frequency distribution?

Accepted Answer

Use the minimum data entry as the lower limit of the first class.

Descriptive Statistics: Frequency Distributions and Their Graphs

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