A study was conducted to estimate , the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 10 hours and that from prior studies, the population standard deviation is assumed to be = 3.6 hours.

We are 95% confident that the mean number of weekly hours that U.S. adults use computers at home falls between what interval?

2. A researcher would like to estimate p, the proportion of U.S. adults who support recognizing civil unions between gay or lesbian couples. Due to a limited budget, the researcher obtained opinions from a random sample of only 1,000 U.S. adults.

With this sample size, the researcher can be 95% confident that the obtained sample proportion will differ from the true proportion (p) by no more than which of the following percentages (answers are rounded)?

3.A researcher would like to estimate p, the proportion of U.S. adults who support recognizing civil unions between gay or lesbian couples.

If the researcher would like to be 95% sure that the obtained sample proportion would be within 1.0% of p (the proportion in the entire population of U.S. adults), what sample size should be used?