When Performing a Rank Correlation Test, One Alternative to Using $$r _ { S } = \pm \sqrt { \frac { t ^ { 2 } } { t ^ { 2 } + n - 2 } }$$

Multiple Choice

When performing a rank correlation test, one alternative to using Table A-9 to find critical values is to compute them using this approximation: $$r _ { S } = \pm \sqrt { \frac { t ^ { 2 } } { t ^ { 2 } + n - 2 } }$$
where $t$ is the t-score from Table A-3 corresponding to $\mathrm { n } - 2$ degrees of freedom. Use this approximation to find critical values of $\mathrm { r } _ { \mathrm { S } }$ for the case where $\mathrm { n } = 7$ and $\alpha = 0.05$ .

A) $\pm 0.569$
B) $\pm 0.755$
C) $\pm 0.448$
D) $\pm 0.669$