Find the sample size: We want to be in plus or minus 2 units. We will have a 90% confidence interval and the population standard deviation is 6. What is the estimated sample size?
A. the estimated sample size lies between 0 and 10
B. the estimated sample size lies between 11 and 20
C. the estimated sample size lies between 21 and 30
D. the estimated sample size lies between 31 and 40
E. the estimated sample size lies between 41 and 60