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Grantham BA215 Assignment 5

Question 1
1. 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.
a. Calculate the mean
of the 20 samples
b. Draw a histogram showing the 20 sample means. (Us classes -0.5 to 0.5, 0.5
to 1.5, 1.5 to 2.5 and so on).
c. Write a page paper – Describe the distribution of the x-bars that you see in part b (shape of
distribution, center, and the amount of dispersion).
d. Draw 20 more samples and add the 20 new x-bars to the histogram in part b.
Write a page paper – Describe the distribution that seems to be developing.
Use the empirical rule
to test for normality. See the sampling distribution of sample means and the
central limit theorem develop from your own data!
Question 2
2.Consider a population with ? = 43 and ? = 5.2.

a. Calculate the
z-score for anx? of 46.5 from a sample of size 35.b. Could this z-score
be used in calculating probabilities using Table 3 in Appendix B? Why or why
not?
Question 3
3.State the null and alternative hypotheses for
each of the following:

a. You want to show an
increase in buying and selling of single-family homes this year when compared
with last year’s rate.
b. You are testing a new recipe for “low-fat” cheesecake and expect to find
that its taste is not as good as traditional cheesecake.c. You are trying to
show that music lessons have a positive effect on a child’s self-esteem.d. You are
investigating the relationship between a person’s gender and the automobile he
or she drives—specifically you want to show that more males than females drive
truck-type vehicles.

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