Question

A pollster contacts 74 people in the 18-21 age bracket and finds that 38 of them respond and 36 refuse to respond. When 297 people in the 22-29 age bracket are contacted, 278 respond and 19 refuse to respond. Suppose that one of the 371 people is randomly selected. Find the probability of getting someone in the 18-21 age bracket OR someone who refused to respond. Round to 3 decimal places.

Answer 1

0,250

Explanation:

The probability that you looking for is sum of probability of getting someone in the 18-27age (74 persones) and probability to getting someone who refused (36 and 19 persones) - probability of getting some of 18-27 age who refused (36 persons).

The probability is:

P(a or b)= p(a)+p(b)-p(a&b)=74/371+(36+19)/371-36/371=0,199+0,148-0,097=0,250