pollsters are

Question

Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 93 people in the 18-21 age bracket and finds that 79 of them respond and 14 refuse to respond. When 261 people in the 22-29 age bracket are contacted, 241 respond and 20 refuse to respond. Assume that 1 of the 354 people is randomly selected. Find the probability of getting someone in the 18-21 age bracket or someone who agreed to respond.

Answer 1

The only way to get someone who is not [in the 18-21 age bracket or agreed to respond] is to get someone who is in the 22-29 age bracket who refused to respond.  There are 20 such people so 

 

P(not[18-21 or agreed]) = 20/354

 

Therefore 

 

P([18-21 or agreed]) = 1 - 20/354 = 334/354 ~ 0.9435