Homework answers / question archive / Question1)A 99% confidence interval for the mean μ, of a population of families in Southern California who have gone to Disneyland, is computed from a random sample of Southern California families and found to be 6 ± 3

Question1)A 99% confidence interval for the mean μ, of a population of families in Southern California who have gone to Disneyland, is computed from a random sample of Southern California families and found to be 6 ± 3

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Question1)A 99% confidence interval for the mean μ, of a population of families in Southern California who have gone to Disneyland, is computed from a random sample of Southern California families and found to be 6 ± 3. We may conclude that

 

 

 

Question 2 

You plan to construct a confidence interval for the mean μ of a Normal population with (known) standard deviation σ. Which of the following will reduce the size of the margin of error?

Question 3 

 

Twenty-five juniors from a University volunteer to allow their Math GRE test scores to be used in a study. These 25 juniors had a mean Math GRE score of 450. Suppose we know that the standard deviation of the population of Math GRE scores for juniors at the University is σ = 100. Assuming the population of Math GRE scores for juniors at the University is approximately Normally distributed, a 90% confidence interval for the mean Math GRE score μfor the population of juniors computed from these data is

 

Question 4 

 

The test grades of a certain population on the Statistics Aptitude Inventory for fifth graders are thought to be Normally distributed with a population mean μ and standard deviation σ = 10. A simple random sample of 25 fifth graders from this population is taken and each is given the Statistics Aptitude Inventory. The mean of the 25 test grades is 104.32. Based on these data, a 95% confidence interval for μ is

 

Question 5 

 

Suppose that two locations with Apple stores (El Capitan and Yosemite) each select random samples of their employees. El Capitan had 5000 employees. Yosemite has 15,000 employees. In both questionnaires, genius techs will record the number of vacation days taken by each employee who is interviewed. If each location randomly selects 3% of its employees, which of the following is true about the sampling distributions of the sample means?