1. The Experimental Hypothesis (H1)....................
Hypotheses
The Experimental Hypothesis (H1)
predicts that there will be a difference between p’s behaviour in the conditions of your study.

2. Spot the difference between the following 2 examples of experimental hypotheses:
1. There will be a difference in the reaction times between p’s who have drunk alcohol and p’s who have drunk water.
2. The reaction times of p’s who have drunk alcohol will be slower that the reaction times of those p’s who have drunk water.

3. So:
A DIRECTIONAL hypothesis predicts the direction of the difference between p’s behaviour in 2 conditions.
A NON-DIRECTIONAL hypothesis DOES NOT predict the direction of the difference between p’s behaviour in the 2 conditions

4. The Null Hypothesis
It is usual to also predict that there will be no difference between p’s behaviour in the 2 conditions of an experiment. This is called the null hypothesis.
TASKS:
Write a null for alcohol & reaction times.
Why do you think we need a null hypothesis?