The Effect Size for the Data from an Independent-Measures T

Multiple Choice

The effect size for the data from an independent-measures t test can be measured by r².Which of the following also produces the value for r²?​

A) ​squaring the Spearman correlation for the same data
B) ​squaring the point-biserial correlation for the same data
C) ​squaring the Pearson correlation for the same data
D) ​taking the square root of the Pearson correlation