# Hyp Testing - H0 The chance of getting a 4,5,6 on a dice is 0.5 H1 The chance of getting a 4,5,6 on a dice is greater than 0.5 So a OTT only tests

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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. A two-tailed test (TTT) measures whether the data you have is “different” from the average. So, for a standard TTT about rainfall, you might have H0 : The average rainfall is 31mm H1 : The average rainfall is NOT 31mm. A one-tailed test (OTT) measures whether the data you have is “higher” (or equally *lower*) than the average - a classic OTT is something like:

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Unformatted text preview: H0 : The chance of getting a 4,5,6 on a dice is 0.5 H1 : The chance of getting a 4,5,6 on a dice is greater than 0.5 So a OTT only tests for deviation in one direction, a TTT does it in both directions (but half as effectively in each). In this case: H0: u = 83 H1: u is not equal to 83 A 90% confidence interval centered on the mean means the same as saying that alpha = 10% Critical value for 2-tail test with alpha = 10%: z = 1.645 test statistic: z(89) = (89-83)/3.5 = 1.714. .. In 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 . This makes yours a OTT, as you are asking whether your class is “better”, not “different”....
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## This note was uploaded on 08/29/2010 for the course ENGINEERIN 305 taught by Professor Martincandell during the Spring '10 term at Rio Hondo College.

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Hyp Testing - H0 The chance of getting a 4,5,6 on a dice is 0.5 H1 The chance of getting a 4,5,6 on a dice is greater than 0.5 So a OTT only tests

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