Question 1. In a study of vehicle speeds on a certain section of highway, a simple random sample of 25 cars resulted in a mean of 60.0 mph with a standard deviation of 4.0 mph. Construct a 90 percent confidence interval estimate of the mean speed (to nearest 0.1 mph) of all vehicles on that section of highway. [Note: Table A-3 might be helpful since the population standard deviation is unknown.] Question 2. Find the sample size required to estimate the mean IQ of all college students. Assume we want a 99 percent confidence level that the sample mean is within 2 IQ points of the true population mean. Also assume that the population standard deviation is 15 IQ points.
Question 1. In a study of vehicle speeds on a certain section of highway, a simple random sample of 25 cars resulted in a
Question 2. Find the
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