320_hw8 - year What assumptions are necessary to do this...

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Economic Statistics: Homework 8 (Estimation) Interval Estimation of Population Mean: Variance Known 1. A random sample of sixteen observations from a normal population with standard deviation of 6 had mean 25. Find a 90% confidence interval for the population mean, μ. 2. A process produces bags of refined sugar. The weights of these bags are normally distributed with standard deviation 1.2 ounces. The contents of a random sample of twenty five bags had mean weight 19.8 ounces. Find a 95% confidence interval estimate of the true mean weight (population) for all bags of sugar produced by the process. Interval Estimation of Population Mean: Variance Unknown 3. A random sample of six cars from a particular model year had the following fuel consumption figures, in miles per gallon: 18.6 18.4 19.2 20.8 19.4 20.5 Find a 99% confidence interval estimate of the population mean for cars of this model
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Unformatted text preview: year. What assumptions are necessary to do this problem? 4. A clinic offers a weight reduction program. A review of its records found the following weight losses, in pounds, for a random sample of ten of its patients the conclusion of the program 18.2 25.9 6.3 11.8 15.4 20.3 16.8 19.5 12.3 17.2 Assuming the population distribution is normal, find a 99% confidence interval estimate for the population mean. 5. The manager of the Inlet Square Mall wants to estimate the mean amount spent per shopping visit by customers. A sample of 60 customers reveals a sample mean of $49.35. a. Determine a 95% confidence interval and interpret the result. b. Suppose the sample was of 60 customers, and yielded the same mean and standard deviation. Determine the 95% CI and compare to part a....
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This homework help was uploaded on 04/22/2008 for the course ECON 320 taught by Professor Martin during the Spring '08 term at Allegheny.

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