Practice Assignment (to be discussed randomly Wednesday, March 3)

1) 5.1 (p. 390)

2) 5.63 (p. 428)

3) Explain the difference between s and s_. Explain the difference between m and m_.

Homework Assignment (Due Friday, March 5) DRAW PICTURES!

1) In your favorite internet browser (e.g. in Information Commons), open the following webpage:

http://www.uop.edu/cop/math/chance/reeses/ReesesPieces.html

It may take a little while to load. You will see a simulation of what we did in class Wednesday. Change the sample size to 25 to mimic what we did in class. My initial guess for the population proportion of orange candies is .45. Click on Draw Samples. The applet takes a sample of 25 candies and plots the value for that sample. Click on Draw Samples a couple more times. Once you "believe" the process, you can change the number of samples to say 50 and unclick the "Animate" button to see the long term behavior of this sampling distribution.

- What is the shape, center, and spread of this distribution?

- What happens (to shape, center, spread) if you increase the sample size to 75?

- What happens if you change the initial guess for the population proportion to .55?

You will notice when you change one of the settings, the old distribution "greys out" for easier comparison.

2) 5.2 (p. 390)

3) 5.4 (p.391) Hint: Review p. 378 and p. 383

4) 5.12b (p. 393) convert to and use the normal approximation

5) 5.26a-c (p. 408-9)

6) Suppose that a random sample of professors is selected from a population with mean age 40 years and standard deviation 5 years.

(a) What are the mean and standard deviation of the sampling distribution?

(b) Describe the shape of the sampling distribution.

(c) Explain why you can predict this shape even though we were not told whether the population of ages followed a Normal distribution.

(d) What is the approximate probability that will be within .5 of the population mean m?

(e) What is the approximate probability that will differ from m (in either direction) by more than .7?

Study hint: Have someone read problems to you from 5.1 and 5.2 without identifying the section. See if you can set up the problem, e.g. means or proportions.

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