A market research firm conducts telephone surveys with a 43%historical response rate.
a. What is the probability that in a new sampleof 400 telephone numbers, at least 160 individuals will cooperateand respond to the questions? In other words, what is theprobability that the sample proportion will be at least 160/400 =0.4?
Calculate the standard error to 4 decimals.
Calculate the probability to 4 decimals, showing your steps alongthe way.
P( ? ) = P(z ? ) =
b. If a follow-up study was completed a year laterwith only 64 telephone numbers, what is the probability that theresponse rate was between 39% and 48%?
Calculate the standard error to 4 decimals.
Calculate the probability to 4 decimals, showing your steps alongthe way.
P( ? ? ) = P( ? z? )= - =
