According to Nielsen/NetRatings, the average visitor to amazon.com spends 19.7 minutes at the site. Assuming this finding to be based on a simple random sample of 20 visitors to the site, with a sample standard deviation of s = 4.0 minutes, and from a population that is approximately normally distributed, construct and interpret the 98% confidence interval for the population mean. Given this confidence interval, would it seem very unusual if another sample of this size were to have a mean visiting time of 18.5 minutes?
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