Q: What is the formula for the relative frequency of a category?

$$\frac{\text{Frequency of the category}}{\text{Total number of observations}}$$

Question 1

Which of the following is a categorical variable?

Accepted Answer

ZIP code of a home

Question 2

What is the formula for the relative frequency of a category?

Accepted Answer

$$\frac{	ext{Frequency of the category}}{	ext{Total number of observations}}$$

Question 3

A survey of 42 students found that 16 preferred comedy movies. What is the relative frequency of students who prefer comedy?

Accepted Answer

$$\frac{16}{42} \approx 0.381$$

Question 4

Which statement is TRUE about the sum of relative frequencies for a categorical variable?

Accepted Answer

It is always equal to 1.

Question 5

In a frequency bar graph, what does the height of each bar represent?

Accepted Answer

The frequency of the category

Question 6

A variable consists of zeroes and ones, where 0 stands for a man and 1 stands for a woman. What type of variable is this?

Accepted Answer

Categorical

Question 7

If a survey of 1081 women and 879 men found that 38% of women and 43% of men identified as Independents, how many more women than men identified as Independents?

Accepted Answer

About 33 more women

Question 8

Which of the following is NOT a correct interpretation of a bar graph showing survey results?

Accepted Answer

The height of the bar for 'Republican' among men is 0.24, so 24% of all American men are Republicans.

Question 9

Which of the following best describes a frequency table?

Accepted Answer

A table that lists all categories and their frequencies

Question 10

Given the following data: 5 students prefer drama, 6 prefer action, 4 prefer thriller, 16 prefer comedy, 5 prefer horror, and 6 prefer other. What is the relative frequency of students who prefer horror?

Accepted Answer

$$\frac{5}{42} \approx 0.119$$

Question 11

Which of the following is a numerical variable?

Accepted Answer

Maximum speed (in miles per hour) of a car

Question 12

If the relative frequency of the 'Action' category is 0.143, what does this mean?

Accepted Answer

14.3% of the class prefers action movies

Question 13

Which of the following is TRUE about a relative frequency distribution?

Accepted Answer

It lists categories and their relative frequencies

Question 14

A student claims that the proportion of men who are Republicans in the survey is the same as the proportion of all American men who are Republicans. What is the best response?

Accepted Answer

The survey proportion may not represent all American men due to sampling error.

Question 15

If you want to find the dates in November 2020 that are both in the third week AND are Thursdays, which date do you select?

Accepted Answer

November 19

Question 16

Which of the following is the correct way to construct a frequency bar graph?

Accepted Answer

List categories on the horizontal axis and draw bars whose heights represent frequencies

Question 17

If the frequency of a category is 6 and the total number of observations is 42, what is the relative frequency?

Accepted Answer

$$\frac{6}{42} = 0.143$$

Question 18

Which of the following is an example of a real-world categorical variable?

Accepted Answer

Blood type (A, B, AB, O)

Question 19

If the sum of the relative frequencies in a table is 0.95, what does this indicate?

Accepted Answer

There is likely a calculation error; the sum should be 1.

Chapter 3: Constructing Graphical and Tabular Displays of Data

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