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Unformatted text preview: Appendix Table 9 lists critical values for upper tail probabilities of 0.05 or 0.01. Therefore, when testing against a two‐sided alternative, the information in the printed table offers a choice of the significance level as either α = 0.10 (a 10% level) or α = 0.02 (a 2% level). In applied work, the computer software is used for the calculation of descriptive statistics, the test statistic and an accompanying p‐value. A p‐value for the two‐tailed test is calculated as: ⎛
p‐value = 2 ⋅ P⎜ F( n − 1 , n − 1 ) > 2 ⎟ y
⎠ For a chosen significance level α , the decision rule is to reject the null hypothesis if: 15 p‐value < α Chapter 11 A one‐sided alternative can also be specified. Test the null hypothesis: H0 : σ 2 = σ 2 X
Y or H0 : σ X ≤ σ Y 2 2 against the alternative: H1 : σ 2 > σ 2 X
Y If a comparison of the calculated sample variances shows s x < s y then there is no evidence to reject the null hypothesis. 2 2 If s x > s y then calculate the test statistic: 2 2 s2
2 sy For a chosen significance level α , the decision rule is to reject the null hypothesis of equal variances if: s2
> Fc s2
y where Fc is the critical value fro...
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- Spring '10