Envision Math 2.0: Grade 8, Volume 1
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5. Interpret Two-Way Relative Frequency Tables
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Exercise 3 Page 240

Recall how we construct a total relative frequency table.

Yes, see solution.

Practice makes perfect

We want to determine whether Maryann is correct in her reasoning.

Maryann's Statement

If 100 people are surveyed, the frequency table will provide the same information as a total relative frequency table.

If we want to make a total relative frequency table based on a frequency table, we need to divide the value of each cell by the number of respondents and multiply it by 100 %. Let x represent the value of cell in the frequency table and n represent the total number of respondents. x/n* 100 % Now let's substitute 100 for n to check whether Maryann is correct.
x/n*100 %
x/100*100 %
x %
We can see that when the total number of surveyed people is equal to 100, the value in a total relative frequency table is the same as the value in the frequency table. The only difference is that in the total relative frequency table, all values are in percentages because they are ratios. Therefore, we can agree with Maryann.

Extra

Real-Life Example

Let's take a look at a real-life example. Suppose that we asked 100 people whether they prefer tea or coffee and we gathered our results in the following two-way frequency table.

Tea or Coffee?
Gender Tea Coffee Total
Male 22 26 48
Female 27 25 52
Total 49 51 100

Now let's create the total relative frequency table by using the method described before.

Tea or Coffee?
Gender Tea Coffee Total
Male 22/100* 100 %=22 % 26/100* 100 %=26 % 48/100* 100 %=48 %
Female 27/100* 100 %=27 % 25/100* 100 %=25 % 52/100* 100 %=52 %
Total 49/100* 100 %=49 % 51/100* 100 %=51 % 100/100* 100 %=100 %

We can see that the values in both tables are the same. This means that if the number of respondents is equal to 100, then the frequency table provides the same information as the total relative frequency table.