Answer
a. Normal
b. 21.1
c. .57
Work Step by Step
a) Using our knowledge of distributions, we see that this distribution is bell-shaped, or normal.
b) The mean of all of the sample means is the same as the mean given in the question, which is 21.1.
c) We find that the standard deviation is:
$\frac{5.1}{\sqrt{80}}=.57$
