Pollsters are concerned about declining levels of cooperation among persons cont
ID: 3222122 • Letter: P
Question
Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 98 people in the 18-21 age bracket and finds that 51 of them respond and 47 refuse to respond. When 270 people in the 22-29 age bracket are contacted, 244 respond and 26 refuse to respond. Suppose that one of the 368 people is randomly selected. Find the probability of getting someone in the 22-29 age bracket or someone who refused to respond refused to respond. P(person is in the 22-29 age bracket or refused to respond=
Explanation / Answer
18-21 total people = 98
51 responded
47 refused to respond
22-29 total people = 270
244 responded
26 refused to respond
P(person is in the 22-29 age bracket or refused to respond) =
Total people in 22-29 age bracket = 270
total people refused to respond = 47 + 26
But 26 who refused to respond from 22-29 age group are common for both sets so will be calculated only once.
Hence total people in the 22-29 age bracket or refused to respond = 270 + 47 = 317
P(person is in the 22-29 age bracket or refused to respond) = 317 / 368 = 0.861