- Directional hypotheses - Direction of change
- Non-directional hypotheses - Change with no direction
- Null hypotheses - State no change
Control of variables
- Extraneous variables - Variables other than the IV that may affect the DV
- Confounding variables - An extraneous variable that affected the DV.
- Demand charateristics - When participants change their behaviour after working out the aim
- Investigator effects - Unwanted influence of the investigator that may influence the results
- Randomisation - The use of chance to control the effects of bias
- Standardisation - Using the same formalised procedures.
- Independent groups - Two seperate groups experience two different conditions
- Repeated measures - All participants take part in all conditions
- Matched pairs - Pairs of participants are matched on some variables that may affect the DV.
- Random allocation - Attempting to control for participant variables in an independent groups design
- Counterbalancing - Attempting to control for the order effects in a repeated measures design
Types of experiment
- Lab - Takes place in a controlled environment/ Control over IV and extraneous variables
- Field - Takes place in a natural setting. Iv is manipulated and DV recorded
- Natural - IV is naturally occuring and records effect on DV
- Quasi - IV is not determined. Strictly not an experiment
- Random - All members of target population ahve an equal chance of being selected
- Systematic - Every nth member of the target population is selected
- Stratified - The composition of sample reflects the proportions of people in certain sub-groups within the target population
- Opportunity - Anyone willing and available is selected
- Volunteer - Participants select themselves to participate
- Informed consent - Participants are made aware of the aims, their rights and what their data will be used for before they take part.
- Protection from harm - Participants should not be placed at any more risk than they would in their daily lives
- Privacy and confidentiality - The right to control information about themselves.
Ways of dealing with ethical issues
- British psychological society has…