Experiements

Experimental Design

Features three main types: Independent Measures, Repeated Measures, and Matched Pairs.
Independent Measures : Involves using two separate groups of participants, one for each condition of the experiment. It eliminates order effects, but participant variables may obstruct results.
Repeated Measures : Uses the same participants in all the conditions of the experiment. It reduces participant variables but risks order effects.
Matched Pairs : Participants are paired based on their similarity on a key variable, and each participant in a pair is allotted to a different condition. This balances the pros and cons of the other two designs.

Hypotheses are predictions made before the start of an experiment. They might be:
Directional Hypotheses: Predicts the direction of the effect (e.g. ‘People who drink energy drinks will perform better than those who don’t’).
Non-Directional Hypotheses (Two-Tailed): Predicts an effect will occur, but not the direction (e.g. ‘Energy drinks will affect performance’).

Questionnaires : Useful for large data collection, but may not capture qualitative information.
- Should have clear, unbiased questions.
- Can be self-administered or researcher administered.
Interviews : Can gather deep insights, but are time-consuming and require skilled interviewers.
- May be structured (set questions), semi-structured (guideline questions), or unstructured (open-ended conversations)

Laboratory Experiments : Conducted in artificial, controlled environments. High control over extraneous variables, but may lack ecological validity.
Field Experiments : Conducted in natural environment, have higher ecological validity, but less control over extraneous variables.
Natural Experiments : Where the independent variable is not manipulated (it occurs naturally). High ecological validity, but cannot establish cause-and-effect relationships.