1) An SRS of 80 teachers found that the average time they have been
standard deviation of 2.3 years. Assuming the distribution of years that teachers have been teaching is
approximately Normal, construct a 95% t-
interval to estimate the population mean of how long teachers
have
been teaching.
(A) 6.5±1.99
2.3
80
(B) 6.5±1.99.
2.3
√80
(C) Cannot be determined because 6.5 - 3*2.3 is negative, so the distribution is not normal
(D) Cannot be determined because we do not know the df to find t*
mined because we do not know the population standard deviation
