Relative Frequency

Relative Frequency

NC Standards

NC.8.SP.4

Understand that patterns of association can also be seen in bivariate categorical data by displaying frequencies and relative frequencies in a two-way table.

• Construct and interpret a two-way table summarizing data on two categorical variables collected from the same subjects.

• Use relative frequencies calculated for rows or columns to describe possible association between the two variables.

Essential Questions

• How can you use two-way tables to display relative frequencies and interpret the pattern in the table?

• How can you use relative frequencies to describe the association between two variables?

• To find relative frequency, set up a ratio comparing frequency/total. Then convert the ratio to a percentage.

• Read questions carefully to determine whether the "total" is referring to the entire table or a specific row or column.

Calculating Relative Frequency

• While frequency is the number of times that something occurs, relative frequency tells us the number of times something occurs compared to the total.

Relative Frequency

Relative Frequency

​1. In a survey of 50 people, 23 individuals answered that their favorite ice cream flavor was vanilla. What was the relative frequency of individuals who chose vanilla? Express your answer as a ratio and a percent.

2. A group of people surveyed were asked whether they have a gym membership and if they floss regularly. Complete each blank space in the two-way table.

3. Of the people surveyed, what is the relative frequency of people who floss regularly?

4. Of the people who own a gym membership, what is the relative frequency of people who floss regularly?

5. Of the people who do not own a gym membership, what is the relative frequency of people who floss regularly?

​Ratio: Percent:

​Ratio: Percent:

​Ratio: Percent:

Multiple Choice

6. Does there seem to be a relationship between people who own a gym membership and people who floss regularly?

• Yes

• No

Liz wanted to see if there was any association between people who have kids and people who have pets. The two-way table shows her results from a survey.

7.

Multiple Choice

d. Does there seem to be any association between people who have kids and people who have pets?

• Yes

• No