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QUESTION 27 A random sample of university students was surveyed to determine the amount of time spent weekly using a personal computer. The times are shown below. If the times are normally distributed with a population variance of 9 hours, estimate with 90% confidence the mean weekly time spent using a personal computer by all university students. The manager wanted to be 90% confident that the true mean was found. Upper Confidence Limit = ? (4 Decimal) QUESTION 28 A random sample of university students was surveyed to determine the amount of time spent weekly using a personal computer. The times are shown below. If the times are normally distributed with a population variance of 9 hours, estimate with 90% confidence the mean weekly time spent using a personal computer by all university students. The manager wanted to be 90% confident that the true mean was found. Lower Confidence Limit =? (4 Decimal) QUESTION 29 A retail store found that about 40 out of 120 sales were coming from the internet. Management wanted to be able to determine what proportion of sales can be expected from the internet. Management wanted to be 95% certain that the estimate will contain the true mean. Sample Size =