statistic 一 問題 (15分)

求教及步驟 thx\r\n\r\n Question is:\r\n\r\n The general manager of a digital products manufacturer believes that 65% of all potential customers prefer to buy MP3 players with over 8GB built-in memory. A random sample of 100 customers was chosen.\r\n\r\n\r\na . If the general manager's brlief is true , what is the mean and the standard deviation of the sample proportion of customers who prefer to buy MP3 players with over 8GB built-in memory?\r\n\r\n\r\nb. If the general manager's belief is true , what is the probability that the sample proportion of customers who prefer to buy MP3 players with over 8GB built - in memory is less than 0.75 ?\r\n\r\n\r\nthx