Finding Relative Frequency

The 30 students in a class did a survey of their favorite movie series and recorded. What was the relative frequency for High School Musical?

• 0,30

• 0,09

• 0,43

• 0,33

Answer explanation

9 students out of 30 said their favorite was High School Musical. Therefore the relative frequency was 9/30 = 3/10 = 0.3

A die was thrown 60 times. What was the relative frequency for a score of six?

Answer explanation

Six occurred 12 times out of 60 throws altogether. Therefore, the relative frequency for a score of six = 12/60 = 1/5 = 0.2

Jane did a count of the number of times each of the vowels occurred on one page of her book. What was the relative frequency of the vowel a?

• 0,200

• 0,120

• 0,126

• 0,210

Answer explanation

First find the total number of vowels on the page

= 126 + 201 + 107 + 120 + 46

= 600

There were 126 a's out of 600 vowels altogether.

So the relative frequency of the vowel a = 126/600 = 63/300 = 21/100 = 0.21

The bar graph shows the usual method of transport to school for the students in a class.

What is the relative frequency of traveling to school by car?

(You may use a calculator)

• 0,60

• 0,27

• 0,67

• 0,30

Answer explanation

The total number of students

= 5 + 1 + 3 + 2 + 6 + 5

= 22

Just add up the heights of all the bars.

Of these, 6 students travel to school by car.

So the relative frequency for traveling to school by car = 6/22 = 0.27 (to 2 decimal places).

The 30 students in a class did a survey of how many pets each of them owned and recorded. What was the relative frequency for a student either owning one pet or owning two pets?

(You may use a calculator)

• 0,457

• 0,353

• 0,667

• 0,553

Answer explanation

12 students out of 30 said they owned one pet and 8 said they owned two pets.

12 + 8 = 20

So the relative frequency was 20/30 = 2/3 = 0.667

The following table shows the sales of TVs made by a retail store each month last year. What was the relative frequency for January?

(You may use a calculator)

• 0,1225

• 0,1325

• 0,1235

• 0,1125

Answer explanation

In January the number of sales was 31, and the total number of sales for the year was 253.

So the relative frequency for January = 31/253 = 0.1225 (to 4 decimals)

Olivia chose a passage from a book and recorded the number of letters in each word. Her results are shown in the following bar graph. What was the relative frequency for 6 or more letters?

• 0,32

• 0,23

• 0,43

• 0,43

Answer explanation

The total number of words in the passage is found by adding the heights of all the bars

= 2 + 8 + 15 + 30 + 22 + 16 + 6 + 1 = 100

The number of words with 6 letters or more = 16 + 6 + 1 = 23

So the relative frequency for 6 or more letters = 23/100 = 0.23

This pie chart shows the McCreedy's household expenditure, broken down into categories. What is the relative frequency for the category 'clothes'?

(You may use a calculator)

• 0,135

• 0,153

• 0,163

• 0,136

Answer explanation

The angle for clothes is 55° and the total angle at the center of the pie chart is 360°

So the relative frequency for 'clothes' = 55/360 = 0.153

The following table shows the sales of DVD players made by a retail store each month last year. What was the relative frequency for the last three months of the year?

(You may use a calculator)

• 0,32

• 0,38

• 0,34

• 0,36

Answer explanation

The total annual sales are found by adding all the monthly sales together

= 25 + 43 + 39 + 28 + 29 + 35 + 32 + 46 + 28 + 43 + 51 + 63

= 462

The number of sales for the last three months = 43 + 51 + 63 = 157

So the relative frequency for the last three months = 157/462 = 0.34 (to 2 decimals)

Anna did a survey where she asked all the children in her school to name their favorite pet. The results are shown in the pie chart. What is the relative frequency for rabbits?

(You may use a calculator)

• 0,05

• 0,03

• 0,11

• 0,07

Answer explanation

The angle for the rabbit is 25° and the total angle at the center of the pie chart is 360°

So the relative frequency for rabbit = 25/360 = 0.07 (to 2 decimals)