Chapter 7.1, Problem 1PB

Simulating the exit poll Simulate an exit poll of 100 voters, using the Sampling Distribution web app accessible from the book’s website, assuming that the population proportion is 0.53. Refer to Activity 1 for guidance on using the app.

1. a. Simulate drawing one random sample of size 100. What sample proportion did you get? Why do you not expect to get exactly 0.53?
2. b. Keep the sample size n as 100 and p as 0.53, but now simulate drawing 10,000 samples of that size. Use the histogram of the 10,000 sample proportions you generated to describe the simulated sampling distribution (shape, center, spread). (Note: The app allows you to save the graph to file.)
3. c. Use a formula from this section to predict the value of the standard deviation of the sample proportions that you generated in part b. Compare it to the standard deviation of the 10,000 simulated sample proportions stated in the title of the graph.
4. d. Now change the population proportion to 0.7, keeping the sample size n at 100. Simulate the exit poll 10,000 times. How would you say the results differ from those in part b?