Consider a random variable x that is normally distributed. complete parts (a) through (d) below. (this is a reading assessment question. be certain of your answer because you only get one attempt on this question.)
(a) if a random variable x is normally distributed, what will be the shape of the distribution of the sample mean?
(b) if the mean of a random variable x is 40, what will be the mean of the sampling distrubution of the sample mean?
(c) as the sample size n increases, what happens to the standard error of the mean?
(d) if the standard deviation of the random variable x is 25 and a random sample of size n-21 is obtained what is the standard deviation of the sampling distrubution of the sample mean?