Compute the sample mean of each sample. Next, create the probability distribution for x. Finally, use your calculator to determine the mean and the standard deviation of xbased on your probability distribution.

Sample (n = 4)	x
12, 13, 17, 20
12, 13, 17, 21
12, 13, 20, 21
12, 17, 20, 21
13, 17, 20, 21

x	probability

=

=

For n = 4 look at the smallest and largest sample means. How close is each of these sample means to the population mean? Use the formula .

This difference is called the sampling error.