We sometimes know the value of one population standard deviation from an extensive history of data, but a new procedure or treatment results in sample values with an unknown standard deviation. If σ1 is known but σ2 is unknown, use the procedures in Part 1 of this section with these changes: Replace s1 with the known value of σ1 and find the number of degrees of freedom using the expression below. Repeat Exercise 13 by assuming that σ = 15 for proctored tests.
Answer to relevant QuestionsIf we use the sample data in Exercise 2, we get this 95% confidence interval estimate: 1.0 mi/gal < µd< 3.8 mi/gal. Treating the same data as independent samples yields —7.8 mi/gal < µ1 - µ2< 12.6 mi/gal for a 95% ...Oscars Use the sample data from Exercise 7 to test for a difference between the ages of actresses and actors when they win Oscars. Use a significance level of a = 0.05. Assume that the paired sample data are simple random ...Self-Reported and Measured Male Heights As part of the National Health and Nutrition Examination Survey, the Department of Health and Human Services obtained self-reported heights and measured heights for males aged 12—16. ...Refer to Data Set 8 in Appendix B and use the times (seconds) that animated Disney movies showed the use of tobacco and the times that they showed the use of alcohol. Use a 0.05 significance level to test the claim that the ...The accompanying table gives results from a study of the words spoken in a day by men and women, and the original data are in Data Set 17 in Appendix B. Use a 0.05 significance level to test the claim that the numbers of ...
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