statistics
posted by ourdes university .
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?

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.
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