A survey was conducted to find the possible relationship between age groups and the most favored of three book genres. The data is represented In the frequency table.
Motivational
Biographies
Do-It-Yourself
40
Total
263
110
21-30 years
113
44
95
219
268
80
92
69
31-40 years
41-50 years
Total
107
153
285
312
750
To the nearest tenth, what percentage of people were in the 41 - 50 age group and favored the Do-It-Yourself books?

C

Step-by-step explanation:

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560