Statistical Hypothesis Testing and Confidence Intervals: AnalyzingReal-World DataQuestion 1A study was conducted to estimateμ, the mean number ofweekly hours that U.S. adults use computers at home.Suppose a random sample of 81 U.S. adultsgives a meanweekly computer usage time of 8.5 hours and that from priorstudies, the population standard deviation is assumed to beσ= 3.6 hours.A similar study conducted a year earlier estimated thatμ, themean number of weekly hours that U.S. adults usecomputers at home, was 8 hours. We would like to test (atthe usual significance level of 5%) whether thecurrentstudy provides significant evidence that this mean haschanged since the previous year.Using a 95% confidence interval of (7.7, 9.3), which of thefollowing is an appropriate conclusion?AThe current studydoesprovide significant evidencethat the mean number of weekly hours has changedover the past year, since 8 falls outside the confidenceinterval.BThe current studydoes notprovide significantevidence that the mean number of weekly hours haschanged over the past year, since 8 falls outside theconfidence interval.CThe current studydoesprovide significant evidencethat the mean number of weekly hours has changedover the past year, since 8 falls inside the confidenceinterval.DThe current studydoes notprovide significantevidence that the mean number of weekly hours haschanged over the past year, since 8 falls inside thePreview Mode
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