1. Hypotheses

2. What is a hypothesis?
A precise and testable statement about the world, specifically about the relationship between data to be tested
A prediction about what the outcome of an experiment will be
It is a statement about populations not samples
Usually derived from a theory

3. Different types Directional hypothesis Non-directional hypothesis
Also known as one-tailed
Non-directional hypothesis
Also known as two-tailed
Experimental / alternative hypothesis
Null hypothesis

4. Directional hypothesis
States the kind of difference or relationship between two conditions or two groups of participants
predicts what way the results will go
Also called one-tailed
When you look at a one tailed cat with butter on the end of its tail you know which way it is going if it wants to lick it off
Example
People who do homework without the TV on will produce better work that those who do homework with the TV on

5. Non-directional hypothesis
Predicts that there will be a relationship between two conditions or two groups of participants
Also known as ‘two-tailed’
This time the cat has two tails with a lump of butter on the end of each one. So which way is the two tailed cat going to go?
Example
There will be a difference in HW produced with the TV on and that produced with the TV off

6. Null Hypothesis (H0)
This is a statement of no relationship between the variables being investigated
Any observed differences between conditions will be down to chance alone
Example
There will be a no difference in HW produced with the TV on and that produced with the TV off

7. Activity
Complete the exercises in the Investigating People Booklet about ‘Hypotheses’.