Question 131436
Is this sample of 25 exam scores inconsistent with the hypothesis that the true variance is 64 (i.e., σ = 8)? Use the 5 percent level of significance in a two-sided test. Show all steps, including the hypotheses and critical values from Appendix E. Exams 
80 79 69 71 74
73 77 75 65 52
81 84 84 79 70
78 62 77 68 77
88 70 75 85 84 
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Ho: sigma^2 = 64
Ha: sigma^2 is not 64
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alpha = 5%; critical Chi-Sq. values for 2-tail test with df=24:
ChL = 12.401 ChR39.364
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Test Statistic: Chi-Sq = (n-1)s^2/sigma^2 = 24*14.068^2/64^2 = 1.1596...
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Conclusion:
Test statistic is < 12.401 so Reject Ho.
Sigma^2 is not 64
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Cheers,
Stan H.