Suppose x has a distribution with a mean of 75 and a standard deviation of 45. random samples of size n = 81 are drawn.

(a) describe the x distribution and compute the mean and standard deviation of the distribution.

(b) find the z value corresponding to x = 90.

(c) find p(x < 90).

(d) would it be unusual for a random sample of size 81 from the x distribution to have a sample mean less than 90? explain.