Types of Hypothesis

Non-Directional Hypothesis

States that the dependant and independant variable will have an effect on one and another but it does not specify what that effect will be.  E.g. Consuming 2 grams of caffeine will alter how much sleep you will get in hours.

Directional Hypothesis

States that the independant variable will effect the dependant variable and the direction of the effect in the experiment. E.g. Consuming 2 grams of caffiene will make you sleep less than 5 hours in one night.

Null Hypothesis

States that if there is an effect between the dependant and independant variables, it is down to chance and not an effect from the experiment. E.g. Consuming 2 grams of caffeine will not influence how much you sleep in one night. It depends on the participant's levels of stress at the time.

Aim

What you are setting out to achieve in the experiment.

Hypothesis

A prediction of the expected outcome in the experiment.