Question 242177: Suppose that the average grade for all people who take this course in statistics is 83 with a standard deviation of 3.5. If your particular class has an average of 89, can you conclude that your class is better than average at the 90 percent confidence level? Label and describe each step of the hypothesis testing procedure, and be sure to specify whether this is a one-tailed or two-tailed test.
Please help, they did not give me a sample size and I am so lost.
Sincerely,
Sarah
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Suppose that the average grade for all people who take this course in statistics is 83 with a standard deviation of 3.5.
If your particular class has an average of 89, can you conclude that your class is better than average at the 90 percent confidence level?
Label and describe each step of the hypothesis testing procedure, and be sure to specify whether this is a one-tailed or two-tailed test.
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Ho: u = 83
H1: u is not equal to 83
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A 90% confidence interval centered on the mean means
the same as saying that alpha = 10%
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Critical value for 2-tail test with alpha = 10%: z = 1.645
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test statistic: z(89) = (89-83)/3.5 = 1.714...
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Conclusion: The test stat is in the reject interval when tested
at the 10% significance level. Reject Ho. Your class results
are better than the average at the 90% confidence level.
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Cheers,
Stan H.
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