Suppose, X1 and X2 have been collected from finite population as (-2, -1,0,1,2} and is the sample mean. Now, calculate E(X) and Var (X). 3. The tear resistance of a type of clothes for 10 samples is as follows: 186, 182, 181, 185, 179, 182, 184, 180, 185, 182 Based on the historical data, the standard deviation of these clothes is 2.5. Determine a 95% confidence interval for population mean of these clothes.