(Solved): n the first semester of the year 2003, the average return for a group of 251 investing companies was ...
n the first semester of the year 2003, the average return for a group of 251 investing companies was 4.5% and the standard deviation was 1.5% . If a sample of 40 companies is randomly selected from this group, what is the approximate probability that the average return of the companies in this sample was between 4% and 5% in the first semester of the year 2003?