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.
Answer
A. (54837.9 , 58142.1)
B. (54637.9 , 60142.1)
C. (54607.2 , 58372.8)
D. (55398.7 , 57581.3 )