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Is a sample correlation coefficient rho = 0.83 significant at the α = 0.01 level based on a sample size of n = 3 data pairs? What about n = 10 data pairs? (Select all that apply.)

a. Significant for n = 3
b. Not significant for n = 3
c. Significant for n = 10
d. Not significant for n = 10

1 Answer

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Final answer:

A sample correlation coefficient of 0.83 is not significant for a sample size of n = 3 at the α = 0.01 level due to the small sample size, whereas it is significant for a sample size of n = 10 at the same α level.

Step-by-step explanation:

To determine if a sample correlation coefficient (ρ) is significant, we consider both the coefficient value and the sample size (n).

Significance for n = 3

With a small sample size of n = 3, the degrees of freedom (df) would be 1 (df = n - 2 = 3 - 2). Even with a ρ of 0.83, the sample size is too small to reach a solid conclusion for most significance levels, including α = 0.01. It is generally not advised to perform significance tests on sample sizes smaller than 5 as they are unreliable. Thus, it is not significant for n = 3.

Significance for n = 10

Assuming a sample size of n = 10, the degrees of freedom would be 8 (df = n - 2 = 10 - 2). When using Table 12.9 or an equivalent critical value table for α = 0.01, you would find much lower critical values than 0.83 for 8 degrees of freedom. This means that a correlation coefficient of 0.83 is well above those critical values, indicating a significant correlation given the sample size and significance level. Hence, it is significant for n = 10.

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