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queenmeg queenmeg
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A professor would like to test the hypothesis that the average grade for a student taking a 10 am statistics class averages five points higher than the average grade from a student in an 8 am statistics class. The following data shows the sample size and average grades for students in the two class times along with the population standard deviations.



Define Population 1 is defined as the 10 am class and Population 2 the 8 am class. Construct an 80% confidence interval for the difference in population mean and interpret the results.
Textbook 

Business Statistics


Edition: 2nd
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nahomf12nahomf12
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More questions for this book are available here
H0: μ1 - μ2 ≤ 0
H1: μ1 - μ2 > 0
zα/2 = 1.28
σ1-2 =  =  = 0.838
UCL1-2 = (1-2) + zα/2σ1-2 
UCL1-2 = (87.1 - 81.4) + (1.28)(0.838) = 6.8
LCL1-2 = (1-2) - zα/2σ1-2 
LCL1-2 = (87.1 - 81.4) - (1.28)(0.838) = 4.6
Because this confidence interval includes 5.0, we fail to reject the null hypothesis. Therefore, the professor cannot conclude that the average grade for a student taking a 10 am statistics class averages five points higher than the average grade from a student in an 8 am statistics class.

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