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For a correlation on 30 pairs of scores, what value of r is needed to achieve significance at alpha=.05

a. .361
b. .355
c. .349
d. 9.49

User Aliassce
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1 Answer

5 votes

Final answer:

The value of r needed to achieve significance at the .05 level with 30 pairs of scores can be determined by referring to a table of critical values for the correlation coefficient using the degrees of freedom, which is n - 2 (28 in this case).

Step-by-step explanation:

The question asks for the value of the correlation coefficient r that is needed to achieve significance at alpha = .05 with 30 pairs of scores. To determine significance, we utilize the degrees of freedom, which in correlation tests is given by n - 2. So, with 30 pairs of scores, the degrees of freedom (df) would be 28. Consulting a table of critical values for the correlation coefficient at the .05 significance level with df = 28, we find the critical value.

If the sample correlation r is greater than this critical value or its negative counterpart (for a two-tailed test), then it is considered significant, meaning the null hypothesis can be rejected, and it is concluded that there is a significant linear relationship between the two variables in question.

User Luzo
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