Addition Rule Example 05

Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 84 people in the 18-21 age bracket and finds that 73 of them respond and 11 refuse to respond. When 275 people in the 22-29 age bracket are contacted, 255 respond and 20 refuse to respond (based on data from "I Hear You Knocking but You Can't Come In," by Fitzgerald and Fuller, Sociological Methods and Research, Vol. 11, 1). Assume that 1 of the 359 people is randomly selected. Find the probability of getting someone in the 18-21 age bracket or someone who responded.