A study was conducted to estimate μ, 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 8.5 hours and that from prior studies, the population standard deviation is assumed to be σ = 3.6 hours.We are 95% confident that the mean number of weekly hours that U.S. adults use computers at home falls between which of the following intervals?Group of answer choices7.7 and 9.37.3 and 9.76.5 and 10.58.4 and 8.68.1 and 8.9

A study was conducted to estimate μ, 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 8.5 hours and that from prior studies, the population standard deviation is assumed to be σ = 3.6 hours.A similar study conducted a year earlier estimated that μ, the mean number of weekly hours that U.S. adults use computers at home, was 8 hours. We would like to test (at the usual significance level of 5%) whether the current study provides significant evidence that this mean has changed since the previous year.Using a 95% confidence interval of (7.7, 9.3), which of the following is an appropriate conclusion? The current study does provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls outside the confidence interval. The current study does not provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls outside the confidence interval. The current study does provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls inside the confidence interval. The current study does not provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls inside the confidence interval. You cannot draw a conclusion because the only way to reach a conclusion is to find the p-value of the test.

A study was conducted to estimate μ, 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 8.5 hours and that from prior studies, the population standard deviation is assumed to be σ = 3.6 hours. The 95% confidence interval for the mean, μ, is (7.7, 9.3).Which of the following will provide a more informative (i.e., narrower) confidence interval than the 95% confidence interval? Check all that apply. Using a sample of size 400 (instead of 81) Using a sample of size 36 (instead of 81) Using a different sample of size 81 Using a 90% level of confidence (instead of 95%) Using a 99% level of confidence (instead of 95%)

Here are the number of hours that 9 students spend on the computer on a typical day:1 6 7 6 8 11 6 12 15Which of the following represents the mean number of hours spent on the computer? 6.0 7.0 8.0 9.0

A simple random sample of seven (7) students is selected, and the students are asked how much time they spent studying for their University subjects (combined) outside class times. From past experience, it is known that these times (in hours) are distributed normally.The times (in hours) for the sample of students are as follows:2.3 7.2 4.5 12.5 6.6 2.5 5.5Based on these results, a confidence interval estimate for the population mean is found to be 5.9 ± 2.6.The level of confidence the researcher has used is closest to:-Group of answer choices95%90%97.5%99%

A study was conducted to estimate μ, the mean commute distance that all employed U.S. adults travel to work. Suppose a random sample of 49 employed U.S. adults gives a mean commute distance of 22 miles and that from prior studies, the population standard deviation is assumed to be σ = 8.4 miles.We are 95% confident that the mean commute distance to work of all employed U.S. adults falls between which of the following intervals? 5.2 to 38.8 19.6 to 24.4 20.8 to 23.2 18.4 to 25.6