A marketing researcher for a phone company surveys 100 people and finds that that proportion of clients who are likely to switch providers when their contract expires is 0.15.
a) What is the standard deviation of the sampling distribution of the proportion?
a) If she wants to reduce the standard deviation by half, how large a sample would she need?As their sample size increases, what's the expected shape of the distribution of amounts purchased in the sample?
b) As the sample size increases, what's the expected shape of the sampling model for the mean amount purchased of the sample?