6.A restaurant would like to estimate the proportion of bills that exceed $100. A quick review of one night's sales reveal an estimate of 0.15 as the proportion. The restaurant would like to construct a 90% confidence interval with a margin of error equal to 0.025. How many bills should the restaurant sample over the next month?

7.Suppose that we are interested in the mean sales price for homes in North Valley, AZ.Performing an audit of all home sales records and their corresponding property tax valuations would be too costly, so we decide to create a representative sample to study.

We determine that the most effective manner would be to only sample homes from Township 2 to minimize our travel time. What kind of random sampling is this? (Possible Answers: Simple Random Sampling, Stratified Sampling, Systematic Random Sampling, Cluster Sampling)

8.Suppose that we are interested in the mean sales price for homes in North Valley, AZ.Performing an audit of all home sales records and their corresponding property tax valuations would be too costly, so we decide to create a representative sample to study.

We determine that the most effective manner would be to place all property tax records in alphabetical order and select every 100th home.What kind of random sampling is this? (Possible Answers: Simple Random Sampling, Stratified Sampling, Systematic Random Sampling, Cluster Sampling)

9.Suppose that we are interested in the mean sales price for homes in North Valley, AZ.Performing an audit of all home sales records and their corresponding property tax valuations would be too costly, so we decide to create a representative sample to study.

We determine that the most effective manner would be to use a random number generator from Excel to determine which properties we should sample. All properties have the same chance of being selected at random. What kind of random sampling is this? (Possible Answers: Simple Random Sampling, Stratified Sampling, Systematic Random Sampling, Cluster Sampling)

10.Suppose that we are interested in the mean sales price for homes in North Valley, AZ.Performing an audit of all home sales records and their corresponding property tax valuations would be too costly, so we decide to create a representative sample to study.

We determine that the most effective manner would be to place the homes in this community into groups:

1. All homes with a pool and a garage
2. All homes with a pool, but no garage
3. All homes with no pool, but with a garage
4. All homes with neither a pool or garage

We will sample 10% of the homes in each group. What kind of random sampling is this?

(Possible Answers: Simple Random Sampling, Stratified Sampling, Systematic Random Sampling, Cluster Sampling)

11.Which of the following will lead to a narrower confidence interval?

Changing the confidence level from 95% to 99%

A decrease in the standard deviation of the sample

Decreasing the sample size