Chapter 11

Degrees of Freedom for an Independent-Samples t Test

df_total = df_X + df_Y

Pooled Variance

Variance for a Distribution of Means for an Independent-Samples t Test

Variance for a Distribution of Differences Between Means

Standard Deviation of a Distribution of Differences Between Means

t Statistic for an Independent-Samples t Test

often abbreviated as:

Confidence Interval for an Independent-Samples

(M_X − M_Y)_lower = −t(s_difference) + (M_X − M_Y)_sample

(M_X − M_Y)_upper = t(s_difference) + (M_X − M_Y)_sample

Pooled Standard Deviation

Effect Size for an Independent-Samples t Test