Question

1. You are interested in the average price of a midsize car. You know the population standard deviation is σ = $3,200. You sample 45 cars and compute a sample mean of $24,550. You decide to summarize your results with a 90% confidence interval.

a. For a 90% confidence interval, what is the value of z*?

b. For your 90% confidence interval, what is the margin of error?

c. Construct the 90% confidence interval. d. Explain briefly what the 90% represents. e. If you wanted a narrower interval, would you choose a 95% confidence interval or an 85% confidence interval?

2. A researcher randomly selects 800 people in the United States and found that 102 of them are dealing with hunger issues.

a. What is the value of the sample proportion?

b. If the researcher is going to compute a 99% confidence interval for the proportion of people in the United States dealing with hunger issues, what is the value of z*?

c. Construct the 99% confidence interval for the population proportion of people in the United States dealing with hunger issues.

Answer 1