Suppose that the average time spent per day with digital media several years ago was 3 hours and 42 minutes. For last year, a random sample of 20 adults in a certain region spent the numbers of hours per day with digital media given in the accompanying table. Preliminary data analyses indicate that the t-interval procedure can reasonably be applied. Find and interpret a 95% confidence interval for last year's mean time spent per day with digital media by adults of the region. (Note: x̄ equals 4.50 hr and s equals 2.18 hr.)
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Robin C.
According to eMarketer, the average time spent per day with digital media in 2010 was 3 hours and 14 minutes. For last year, a random sample of 20 American adults spent the following number of hours per day with digital media: 1.4, 5.0, 5.8, 4.1, 5.6, 2.1, 6.5, 2.3, 8.0, 9.5, 7.3, 5.9, 9.4, 4.3, 2.9, 2.8, 5.1, 4.5, 4.1, 6.6 a. Obtain and interpret a 90% confidence interval for last year's mean time spent per day with digital media by American adults. (Note: μ = 5.16 hr; s = 2.3 hr.)
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