Hypothesis- is a precise, testable statement of what the
researchers predict will be the outcome of the study.
Types of Hypotheses:-
Directional (One tailed hypothesis) - direction of difference is stated.
E.g. there will be a higher amount of orange juice consumed in the
hot room compared to the cold room.
Non-directional (Two tailed hypothesis) - where direction of
difference isn’t stated but that there will be a difference in the
conditions.
E.g. there will be a difference between the amount of orange
consumed in the hot and cold conditions.
Situations where two tailed experiments should be used:-
There is a disagreement between researchers
Research has not been carried out previously
Null Hypothesis
Results are due to chance and the temperature of room has had no effect
at all on the amount of orange juice consumed
Experimental Method
Independent variable – Variable changed by researcher
Dependent variable – variable measured by researcher
Extraneous variable- variable that don’t vary systematically with the IV.
It affects the DV.
Cofounding variable-variable that vary systematically with the IV.
Pilot study – small- scale trial run of a study to test any aspects of the
design, with a view to making improvements.
Confederate – individual in a study who is not a real participant and has
been instructed how to behave by the investigator
, Experimental designs
Repeated Measures
Participants take part in both conditions
Strengths
- No individual differences
Weaknesses
- Order effect - performance affected in condition 2 due to
experiences as you’ve had practice
- Demand Characteristics – may have guesses the aim of the study
- Fatigue characteristics – bored or tired
Independent group design
Participants only take part in one condition of the experiment (2 separate
groups)
Strengths
- No order effect - performance isn’t affected in condition 2 due to
participants only taking part in one condition
- No demand Characteristics – less likely to guess aim of experiment
- No fatigue characteristics – less likely to get bored or tired
Weaknesses
- Participant variables- e.g. individual differences
- Need double the number of participants
Matched pair designs
Participants are matched in each condition for characteristics that may
have an effect on their performance
Strengths
- Limits participant variables
- No order effect
Weaknesses
- Difficult, timely, expensive to match people
- No two people are the same
To get around order affects you can counterbalance (balance effect of
situational variables of order effects)
E.g. Split group in half where one group does condition 1 first and other
group does condition 2 first