Hypothesis testing –Revisited A method for deciding whether the sample that you are looking at has been changed by some type of treatment (Independent Variable IV) Looking at how likely it is that a sample like the one that you have would be selected at random (without the benefit of treatment).

Sampling Distribution Mean values of all possible samples. Frequency How many samples  xx

Sample means Z scores H1H1 H1H1 p = <.025

Sample means Z scores H1H1 H1H1 Z = is more extreme than -1.96

Sample means Z scores H1H1 H1H1 p = >.025

Sample means Z scores H1H1 H1H is less extreme than 1.96 Z = 1.96