Two independent samples each have n = 4 scores. If the first sample has a sum of squares of 30 and the second sample has sum of squares of 18, what is the estimated standard error for the sample mean...

Two independent samples each have n = 4 scores. If the first sample has a sum of squares of 30 and the second sample has sum of squares of 18, what is the estimated standard error for the sample mean difference,  Sm1-m2?

a.           1

b.           2

c.           4

d.           Cannot determine without more information