A study was conducted to determine if the salaries of librar

A study 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 mu_1 - mu_2.

Solution

df = 28
  standard error of difference = 804.156

95% confidence interval of this difference: From -3047.24 to 247.24

(-3047.24, 247.24)

Group	Group One	Group Two
Mean	28900.00	30300.00
SD	2300.00	2100.00
SEM	593.86	542.22
N	15	15