The researcher's null hypothesis is H₀: σ² = 420. A sample of n = 18 items yields a sample variance of s² = 512. The critical values of chi-square for a two-tailed test at α = .05 are: A)8.672 and 27.59 B)7.564 and 30.19 C)-1.960 and +1.960 D)9.390 and 28.87

Question

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The critical values of chi-square for a two-tailed test depend on the degrees of freedom (n-1) and the significance level (α). For n = 18, degrees of freedom = 17. At α = .05 for a two-tailed test, the critical values for 17 degrees of freedom are 7.564 and 30.19, which correspond to the lower and upper critical values, respectively. Choices A, C, and D do not match the correct critical values for a chi-square distribution with 17 degrees of freedom at the .05 significance level.

The Researcher's Null Hypothesis Is H0: σ2 = 420

The Researcher's Null Hypothesis Is H₀: σ² = 420