Pooled Two Sample T Test Formula. Two sample assuming equal variances from the data data analysis menu. When we use the pooled t test the assumption is that the degrees of freedom is given by df n 1 n 2 2.
Sp n1 1 s12 n2 1 s22 n1 n2 2 where s12 and s22 are the sample variances. Now we draw the t distribution with df 12 degrees of freedom and shade the region corresponding to the t statistic. For this reason the pooled variance method should be used with caution.
Where s 1 and s 2 are the standard deviations of the two samples and n 1 and n 2 are the sizes of the two samples.
Independent samples pooled standard devation the equal variance assumption. When the sample sizes are equal b true or b false yields the same result. S2 p s2 1 s2 2 2 s p 2 s 1 2 s 2 2 2. It estimates the difference between the two unknown population means.
