Using the telephone numbers listed in your local directory as your population, randomly obtain 20 samples of size 3. From each telephone number identified as a source, take the fourth, fifth, and sixth digits. (For example, for 245-8269, you would take the 8, the 2, and the 6 as your sample of size 3.)

a. Calculate the mean of the 20 samples.

b. Draw a histogram showing the 20 sample means. (Use classes 0.5 to 0.5, 0.5 to 1.5, 1.5 to 2.5, and so on.)

c. Describe the distribution of x’s that you see in part b (shape of distribution, center, and amount of dispersion).

d. Draw 20 more samples and add the 20 new x’s to the histogram in part

b. Describe the distribution that seems to be developing.