Astudy was conducted to determine if the salaries of librarians from two neighboring cities were equal. a sample of 15 librarians from each city was randomly selected. the mean from the first city was $28,900 with a standard deviation of $2300. the mean from the second city was $30,300 with a standard deviation of $2100. construct a 95% confidence interval for u1 -u2.
a.) (-4081, 597)
b.) (-2054, 238)
c.) (-2871, 567)
d.) (-3125, 325)