Explore: Two-Way Tables (cont.) Solutions

Two-Way Tables (cont.) Solutions

A relative frequency table contains proportions or percentages rather than counts. 
- Since most groups are not equal in size , percentages allow for a more fair comparison of events (or subgroups). 
Joint relative frequency tables calculate proportions or percentages out of the population total . 
- The proportion or percentage is calculated from the population total.

Note

Because proportional relationships exist in more than one way, there is more than one type of relative frequency table. Row and column relative frequency tables, including ones that use the row or column totals, are other types of frequency tables, but are not covered in this level.

Example 6

A group of 200 athletes was asked if they ate a snack and if they completed a warm-up before their games.

Determine the number of athletes that fit the description.

Athletes who did not complete a warm-up

$P (W ’) = 5 % + 6 % = 11 % (0.11) (200) = 22 athletes$

Athletes who did not snack and completed a warm-up

$P (S ’ \cap W) = 44 % (0.44) (200) = 88 athletes$

	W	W’	Total
S	45%	5%	50%
S’	44%	6%	50%
Total	89%	11%	100%

Note

This is a joint frequency table because the percentages are out of the population total.