1. (To do with R software) Consider a sample X1, ....,X5 (i.i.d) as a random variable X which gives the normally distributed with a mean of X and variance 2. Another sample Y1, ...., Y8 (i.i.d) as a random variable Y which gives the normally distributed with mean Y and variance 2. (a) Use the following data to check the normality of the data and whether we can assume that the 2 variables have unknown variances but which can be assumed to be equal or not. (b)Based on your answer to question (a) nd a 90% condence interval for X Y : x1 = 644; x2 = 493; x3 = 532; x4 = 462; x5 = 565 and y1 = 623; y2 = 472; y3 = 492; y4 = 661; y5 = 540; y6 = 502; y7 = 549; y8 = 518