To construct a confidence interval for the difference between two population means u1-u2, use the formula shown below when both population standard deviations are known, and either both populations are normally distributed or both n1 is (greater than or equal to) 30 and n2 is (greater than or equal to) 30. The descriptive statistic for the annual salaries from a random sample of microbiologists from two regions are shown below. Construct a 95% confidence interval for the difference between the mean annual salaries.
x1= $103,040, n1=40, and o1=$9050; x2=$85,420, n2=45, and o2=$9030