Question

A study was conducted in order to estimate u, the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults give a mean weekly computer usage time of 8.5 hours and that from prior studies , the population standard deviation is assumed to be 3.6 hours.

Answer 1

Are you looking for the confidence interval?

What level of significance are you using?

95% = mean ± 1.96 SEm

SEm = SD/√n

Answer 2

n a planned study, there is a known population with a normal disrubution, \mu= 0, and \sigma=10. What is the predicted effect size (d) if the researchers predict that those given an experimental treatment have a mean of (a) -8, (b) -5, (c) -2, (d) 0, and (e) 10 ? For each part, also indicate wether the effect is approximatley small, medium, or large.