1.We have calculated a 95% confidence interval for the difference between two population proportions. The interval is 4% +/- 5%. Can we conclude that there is a significant difference between the two group population proportions? Yes or No? Explain briefly.

2.A random sample of 900 homeowners in Allegheny County is taken in order to estimate the average amount of money spent by homeowners on landscaping this spring. It turns out that this group spent an average of $200 with a standard deviation of $150. A 95% confidence interval for the average amount spent on landscaping by all Allegheny County homeowners is calculated to be $200 $10. Which is true about this situation?

A)The true average amount spent must be in this interval.

B)The procedure used here produces intervals that cover the right answer for 95% of all samples.

C)This confidence interval won't cover the right answer since a histogram of the amount spent is skewed.

D)The interval would be wider if we used an 80% confidence level instead of 95%.

3.A random sample of 900 homeowners in Allegheny County is taken in order to estimate the average amount of money spent by homeowners on landscaping this spring. It turns out that this group spent an average of $200 with a standard deviation of $150. In this situation, what is the population? What is the parameter? What is the sample? What is the statistic?

4.One thousand students are randomly selected from the list of those currently registered at Harvard University, and they each report how many miles they rode in an MTA bus during the past week. Because many students did not ride a bus at all, a histogram of the values does not look like the normal curve. True or False: Even though the histogram did not follow the normal curve, it is still possible to use the normal curve to make a confidence interval for the average number of miles that all Harvard students rode on MTA buses last week. (explain briefly why you chose your answer).