Aims and hypotheses

• Hypotheses are not predictions, they are statements of fact
• Null hypothesis (H0)


  There is no difference between the conditions or no relationship between the variables
• Alternate hypothesis (H1)


  There is a difference between the conditions, also known as the research hypothesis
• Directional hypothesis


  States that there is a difference and how the results will go (e.g. increase, decrease)
• Non-directional hypothesis


  States that there is a difference but not which way the direction will go
• In psychology, the alternate hypothesis is accepted when the probability that the results are a fluke is 1 in 20 or less (p ≤ 0.05)
• Accepting an alternate hypothesis is not proving a theory, it is saying the evidence is strong enough to accept it for now
• The word "prove" should not be used in science, as theories must be open to falsification