Arandom sample of size n1 = 16 is selected from a normal population with a mean of 75 and a standard deviation of 9. a second random sample of size n2 = 8 is taken from another normal population with mean 69 and standard deviation 10. let x1 and x 2 be the two sample means. find: a. the probability that x1 - x2 exceeds 4.b. the probability that 4.3 < = x1 - x2 < = 5.0.