A correlation is computed for a sample of n = 18 pairs of X and Y values. What correlations are statistically significant with ? = .05, two tails. 1. correlations greater than or equal to 0.456 and correlation less than or equal to Solution df=N-2=18-2=16 so from the table critical values are 0.468 and -0.468 so 3. correlations greater than or equal to 0.468 and correlation less than or equal to.