Posted by Tanya on .
At a recent scotch-tasting party, 20 faculty members and their (opposite sex) spouses were guzzling it back pretty well. One person quite correctly noticed that the women seemed to be drinking more than the men. If the mean number of drinks had by the men was 5, and that for the women was 7.2, and the standard deviation for the whole group was 2 drinks, what was the correlation between gender and the number of drinks consumed?
Cohen's d is the difference between two means divided by a standard deviation.
Calculate Cohen's d (d) and the effect-size correlation (r) using the following formulas:
d = (M1 - M2) / s
r = d / √(d^2 + 4)
With your data:
d = (7.2 - 5) / 2 = 1.1
r = 1.1 / √(1.1^2 + 4) = 0.48
Check these formulas and calculations.