A random sample of size 100 is drawn from a population with a standard deviation of 10. If only 5% of the time a sample mean greater than 20 is obtained, the mean of the population is ______.

Answer 1

Z = (score-mean)/SEm

SEm = SD/√n

Assuming a normal distribution, find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.05) and its Z score. Insert Z score and other data into the top equation and solve for the mean.

Answer 2

258