You suspect that your Toronto customer support team differs in the time to serve each customer from your Montreal team. You gathered a sample from each group, included in the Excel file. Assume that you know the standard deviation for each population (4.1 for Toronto, 3.8 for Montreal). For this question, perform your calculation using the formulasdo not use the Analysis Toolpak tools.

Part a)

Calculate a 99% confidence interval for the difference between population means.

Part b)

You suspect that the population mean for Toronto is at least 4 greater than for Montreal. Perform a hypothesis test, using the p-value method, at a 90% confidence level. Show all parts of the hypothesis test, including your hypotheses, identification/calculation of the necessary values, your test-statistic calculation, your p-value calculation, and your conclusion.