Posted by ourdes university on .
a sample of 100 persons had a mean of 80 for a measure and the population standard deviation of 5. what ia the 99% confidence interval for the mean?

statistics 
PsyDAG,
99% = mean ± 2.575 SEm
SEm = SD/√n
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.