Let’s say we have a population comprised of four typists with the following numbers of errors per page of a manuscript:

Stephanie X1=3

Adam X2=2

Leslie X3=1

Shay X4 =4

What is the population average errors per page (if these four individuals comprise the entire population)?

What is the population standard deviation? Remember to use population, not sample formulas.

OK, now for the fun part: How many random samples of 2 typists can be formed from this population of 4 (assume that you are sampling with replacement)?

For each sample of two, solve for the average errors per page. Now, take the average of all the sample averages. What do you get? Why?

Finally, elaborate a little bit on the difference in values between the population standard deviation versus the standard error of the mean.