Can anybody help me with this quesiton???
To ascertain the effectiveness of the advertising campaign for the Red Cross Annual Appeal on donations, a telephone survey of 306 Brisbane residents was conducted. Two of the questions asked were
1. Did you see the advertisement for the Annual Appeal?
2. Did you donate to the Appeal?
203 of the respondents indicated they had seen the advertisement, with 13 of these not donating tothe Appeal. Overall, 80 respondents had not donated to the Appeal. If one of the respondents was chosen at random, what is the probability that he saw an advertisement and gave a donation? (3 dec pl)
13 of those who saw the ad gave, so of the 203 who saw the ad 203-13 gave.
Originally Posted by sky_sa35
So p(saw ad and gave)=(203-13)/306