A) Compute sample mean and sample standard deviation B) Using results form part (A) build a 90% confidence interval around population mean and interpret it.Suppose X1, X2 and X3 are independent random variables such that E[X ] = 0 , for i=1,2,3 E[X *]= 1, for i=1,2,3 What is E[X1 "(X2 - 4X;) ] =? (E=Expectation)Confidence Interval: In a marketing study a sample of 10 customers are randomly selected and their preference for a product record (on the scale of 1 to 10). The result is as follows: ID preference 1 3 2 4 3 3 4 6 7 iin 6 4 10 1 9 9 10 8