Group 1 (Praise): N₁ = 4, M₁ = 10.5, SS₁ = 5
Group 2 (Abuse): N₂ = 5, M₂ = 8.2, SS₂ = 14.8
Estimate the standard deviation of the sampling distribution (i.e. the 'standard error').
est.(₁ − ₂)=?