A Large Population of Peer Ratings of Physical Attractiveness Is

Short Answer

A large population of peer ratings of physical attractiveness is approximately normal with

and

We plan to select a random sample of four ratings from this population. What is the probability of obtaining a sample mean
(a) above 6.0
(b)below 4.0
(c)between the population mean and .5 above the mean
(d)no more than .5 away from the population mean (in either direction)
(e)What sample mean has such a low value that the probability is .05 of obtaining one as low or lower?
(f)What are the centrally placed limits such that the probability is .95 that the sample mean will fall within those limits?