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Many employers are concerned about employees wasting time by surfing the Internet and e-mailing friends during work hours. The article "Who Goofs Off 2 Hours a Day? Most Workers, Survey Says" summarized data from a large sample of workers. + Suppose that the CEO of a large company wants to determine whether the mean wasted time during an 8-hour workday for employees of her company is less than the mean of 120 minutes reported in the article. Each person in a random sample of 10 employees is asked about daily wasted time at work (in minutes). Participants would be guaranteed anonymity to obtain truthful responses. Suppose the resulting data are as follows. 131, 148, 136, 120, 111, 88, 102, 113, 87, 110 (a) Calculate the point estimate (in minutes) for the population mean. min (b) Assume that the population standard deviation is known to be o = 54.8 minutes. We would like to estimate the population mean with 95% confidence. Calculate the margin of error (in minutes) of the point estimate. (Use a table or technology. Round your answer to three decimal places.) min (c) Find a 95% confidence interval. (Round your answers to three decimal places.) min N DETAILS MY NOTES ASK YOUR TEACHER Suppose that you calculated the sample size needed to estimate a population mean within a given margin of error when o is known, and the answer came out to n = 36.02. How many items should be sampled? 36 30 O'37 36.02 DETAILS MY NOTES ASK YOUR TEACHER The sampling distribution of the sample mean is approximately normal when which of the following are true? (Select all that apply.) On 2 30 The population distribution is approximately normal. On 2 10 Ons 30