What method/ process should I use in order to solve this? It’s due in one day.

Question

Large adult population has a mean IQ of 113, standard deviation of 25. Suppose 40 are randomly selected for a market research campaign.(z-values (2 decimal places) and rest of the answers to 4 decimal places)

a) what’s the standard deviation?

b) how to calculate probability of the sample mean IQ if it is less than 112? The probability that it is less than 112 is ___

c) refer to b, what if it’s greater than 112?

e) what is the probability that the sample mean is between 112 and 117?

Answer 1

a) what’s the standard deviation? 3.95

b) The probability that it is less than 112 is _0.4008__

c) greater than 112? 0.5992

e) probability that the sample mean is between 112 and 117? 0.4417