Counting Rule for Combinations

The equation for the estimated pooled variance is: s p 2 = s M 2 n M -1 + s F 2 n F -1 n M + n F -2 . Note that the estimated pooled standard deviation, s p , is calculated by taking the square root of the pooled variance estimate s p = s p 2 . Using the values from Table 2, students should find the pooled standard deviation estimate to be: ... ................
................