Question:

Answer the following questions showing all work. If you use Minitab Express include the appropriate output (copy + paste) along with an explanation.  Output without explanation will not receive full credit. Round all answers to 3 decimal places. If you have any questions, post them to the course discussion board.

1. For each of the following, compute the correct degrees of freedom and find the correct t multiplier for constructing a confidence interval for a population mean using Minitab Express.

A. Confidence level 85%, , df = _____, t* = ______

B. Confidence level 85%, , df = _____, t* = ______

C. Confidence level 95%, , df = _____, t* = ______

D. Confidence level 95%, , df = _____, t* = ______

E. How does the t multiplier change as the confidence level changes?

F. How does the t multiplier change as the sample size changes?

2. For the following scenarios, if you were to construct a confidence interval, what would be the appropriate multiplier?  (State whether z* or t* AND look up the number) [20 points]

A. You want to estimate the proportion of Penn State students who own a Mac with 95% confidence. You take a simple random sample of 30 Penn State students.

B. You want to estimate the average weight of female Maine Coon cats with 95% confidence.  You have a sample of 16 female Maine Coons.

C. You want to construct a 99% confidence interval for the mean number of credits completed by students enrolled in STAT 200 this semester across all campuses. You take a random sample of 850 students.

D. You want to construct a 90% confidence interval for the proportion of registered Pennsylvanian voters who plan to vote for Candidate A. You take a random sample of 50 registered voters in Pennsylvania.

E. You want to construct a 90% confidence interval for the average height of all Penn State World Campus students.  You have a random sample of 27 World Campus students.