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# Quiz 1 solutionsdoc - Res 342 Quiz 1 Ron Konnick 1(2 points...

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Res 342 Quiz 1 Ron Konnick 1. (2 points) What does a confidence interval tell you? What does it mean? A confidence interval gives two numbers that have a stated probability of includeing the value of the parameter of interest. For example a “95% confidence interval” says that there is a 95% chance that the interval contains the actual parameter values. What two things can a researcher do to reduce the width of a confidence interval? What are the effects? The sample size can be increased. Of course there will be additional cost involved. The other other option is to decrease the confidence level. This means there will be a smaller probability that the interval will contain the value of the population parameter. 2. (4 points) Compute the 95% confidence interval on the population mean if a sample of 1000 is taken and the sample mean is found to be 15.95 and standard deviation is 4.2. Large sample, confidence interval on the mean. The formula of interest is n zs X ± The z value for a 95% confidence interval is 1.96. Plugging in the sample values

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Quiz 1 solutionsdoc - Res 342 Quiz 1 Ron Konnick 1(2 points...

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