# Question: To compare the variations in weight of four breeds of

To compare the variations in weight of four breeds of dogs, researchers took independent random samples of sizes n1 = 8, n2 = 10, n3 = 6, and n4 = 8, and got σ21 = 16, σ22 = 25, σ23 = 12, and σ24 = 24. Assuming that the populations sampled are normal, use the formula of part (b) of Exercise 12.25 to calculate –2 · ln λ and test the null hypothesis σ21 = σ22 = σ23 = σ24 at the 0.05 level of significance. Explain why the number of degrees of freedom for this approximate chi-square test is 3.

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