What is the effect size (Cramér's ) for a 3 × 3 table for N = 150 and a chi-square value = 9.49? Use the following formula:

A) .25
B) .06
C) .03
D) .18

To calculate Cramér's phi, we first need to calculate the square root of chi-square divided by N (number of observations):

sqrt(9.49/150) = 0.251

Then we use this value to calculate phi:

phi = sqrt(0.251 / (3-1)) = 0.354

Finally, we divide phi by the square root of the number of rows minus 1 (or the number of columns minus 1, which should be the same for a 3x3 table) to get the effect size:

0.354 / sqrt(2) = 0.250

So the effect size is approximately 0.25, which corresponds to choice D.