In: Statistics and Probability
A random sample of 1515 teachers from Winnipeg produced an average annual salary of $35,270 with a standard deviation of $3,256. A random sample of 2020 teachers from Brandon produced an average salary of $32,268 with a standard deviation of $2,532
a) (7 points) Using critical value approach test at 2%significance level whether the true mean annual salaries for all teachers in both cities are different? State the assumption(s) required for the test.
b) (3 points) Construct a 98% confidence interval for the difference between true mean annual salaries and test the hypothesis in (a).