# I needed help with assignment

**Question description**

Assignment Week 5

link rel="stylesheet" type="text/css" media="screen" href="https://content.grantham.edu/at/Styles/BA215/BA215.css" />

Question 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.

- Calculate the mean of the 20 samples
- 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).
- Describe the distribution of the x-bars that you see in part b (shape of distribution, center, and the amount of dispersion).
- Draw 20 more samples and add the 20 new x-bars to the histogram in part b. 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

Consider a population with μ = 43 and σ = 5.2.

- Calculate the z-score for an x? of 46.5 from a sample of size 35.
- Could this z-score be used in calculating probabilities using Table 3 in Appendix B? Why or why not?

Question 3

State the null and alternative hypotheses for each of the following:

- You want to show an increase in buying and selling of single-family homes this year when compared with last year’s rate.
- You are testing a new recipe for “low-fat” cheesecake and expect to find that its taste is not as good as traditional cheesecake.
- You are trying to show that music lessons have a positive effect on a child’s self-esteem.
- 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.

## Tutor Answer

Brown University

1271 Tutors

California Institute of Technology

2131 Tutors

Carnegie Mellon University

982 Tutors

Columbia University

1256 Tutors

Dartmouth University

2113 Tutors

Emory University

2279 Tutors

Harvard University

599 Tutors

Massachusetts Institute of Technology

2319 Tutors

New York University

1645 Tutors

Notre Dam University

1911 Tutors

Oklahoma University

2122 Tutors

Pennsylvania State University

932 Tutors

Princeton University

1211 Tutors

Stanford University

983 Tutors

University of California

1282 Tutors

Oxford University

123 Tutors

Yale University

2325 Tutors