A study was conducted in order 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), our conclusion is that:
Our conclusion is that the mean number of weekly hours that U.S. adults use computers at home is 8 hours
Explanation:
8 hours falls in the 95% confidence Interval (7.7, 9.3), so we can conclude that the mean weekly hours that U.S. adults use computers at home is 8 hours
