Weather Forecasters Would Like to Report on Temperatures in Washington

Short Answer

Weather forecasters would like to report on temperatures in Washington, DC. In particular, they would like to compare the temperatures in December to temperatures in January to help potential tourists understand whether there is a difference. The average December temperature in a random sample of 16 days is 35 and the average January temperature in a random sample of 20 days is 33. The standard deviations based on historic information are 4 for December and 5 for January.
A) Construct a 90% confidence interval for the difference between the population mean temperatures in December and January.
B) Can we conclude with 90% confidence that the mean temperatures in December and January are different?