The Formula $s _ { \text {difference } } = \sqrt { S ^ { 2 } \text { difference } }$

Multiple Choice

The formula $s _ { \text {difference } } = \sqrt { S ^ { 2 } \text { difference } }$ is used to calculate the:

A) pooled variance estimate.
B) standard deviation for an independent-samples t test.
C) squared standard error.
D) estimated standard deviation of the distribution of mean differences.