Suppose that there are three different populations we want to compare, say P 1 , P 2 and P 3 . Each of

these populations are normal. A random sample from each population is taken and the results are given

below.

P 1 P 2 P 3

10 6 5

12 8 9

9 3 12

15 0 8

13 2 4

a) Find the sample means and sample variance for each sample. Use Excel and record the results in

your Word document.

b) Combine all samples and find the mean of the data set with 15 data points. Call this the grand

mean.

c) develop a graph that illustrates the sample means and the grand mean. Copy and paste your graph

into your Word document.

d) Based on parts a, b and c do the sample means appear to be approximately equal?