5. The independent random variables X and Y have distributions with the same variance. Random samples of 6 observations of X and 10 observations of Y are taken, and the results are summarized by 2:: = 5.33::2 = 11.2}: = 10,232 = 160. (a) Find a pooled estimate of the variance . [5] (b) Find also, a 99% condence interval for the difference between the population means ofX and Y. [4]