Reference no: EM132465249

1. For each of the following statements, indicate whether it is True/False. If false, explain why.

I. If the 95% confidence interval for the average purchase of customers at a department store is $50 to $110, then $100 is a plausible value for the population mean at this level of confidence.

II. If the 95% confidence interval for the number of moviegoers who purchase concessions is 30% to 45%, this means that fewer than half of all moviegoers purchase concessions.

III. The 95% Confidence-Interval for μ only applies if the sample data are nearly normally distributed.

2. For each of the following statements, indicate whether it is True/False. If false, explain why.

I. The sample size of the survey should at least be a fixed percentage of the population size in order to produce representative results.

II. The sampling frame is a list of every item that appears in a survey sample, including those that did not respond to questions.

III. Larger surveys convey a more accurate impression of the population than smaller surveys.

3. Which is shorter: a 95% z-interval or a 95% t-interval for μ if we know that σ =s?

A. The z-interval is shorter

B. The t-interval is shorter

C. Both are equal

D. We cannot say