Posted by Alison on .
An economist found that a random sample of 42 high school teachers had an average annual salary of $56,490. A previous study showed that the population standard deviation is $4150. Find the 99% confidence interval for µ, the average annual salary of all high school teachers.

Statistics 
PsyDAG,
99% = mean ± 2.575 SEm
SEm = SD/√n
I'll let you do the calculations.