Question

practice working with relative frequency tables. weekend curfews determine the values of the letters to complete the conditional relative frequency table by column. 16 years old 17 years old total a = b = before 10 p.m. 0.9 b 0.88 after 10 p.m. a 0.15 0.12 total 1.0 1.0 1.0

Explanation:

Step1: Use column - total property for 16 - year - olds

In the column for 16 - year - olds, the sum of the relative frequencies of "Before 10 p.m." and "After 10 p.m." must be 1. So, if the relative frequency of "Before 10 p.m." is 0.9, then for the 16 - year - olds column, we have $a+0.9 = 1$.
$a=1 - 0.9$

Step2: Use column - total property for 17 - year - olds

In the column for 17 - year - olds, the sum of the relative frequencies of "Before 10 p.m." and "After 10 p.m." must be 1. So, if the relative frequency of "After 10 p.m." is 0.15, then for the 17 - year - olds column, we have $b + 0.15=1$.
$b=1 - 0.15$

Answer:

$a = 0.1$
$b = 0.85$