Hypotheses

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

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

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

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

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

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