AQA GCSE Psychology Unit 4 - Research methods

Aim

a statement that explains the purpose of a study

Independent and Dependent Variables

• The Independent Variable (IV) is the factor which is changed/manipulated

• Dependent Variable (DV), which is the variable being measured

Extraneous Variables

Variables which affect the DV but are not manipulated by the researcher

hypothesis

testable statement written as a prediction of what the researcher expects to find as a result of their experiment

Alternative and Null hypotheses

• The alternative Hypothesis is a hypothesis that states that the IV will affect the DV, wheras a null hypothesis states the opposite

Operationalisation

Clearly defining variables in terms of how they could be measured

Methods of standardisation

• instructions: ppts all recieve the same information

• procedures: the ppts environment/instructions/experience should be the same unless the difference is the independent variable

• randomisation: make sure there are no biases in procedures

Reliabilty

whether a study would produce similar results if repeated

e.g. if repeated with different stimulus material and find similar results reliability is high

Validity

whether the reasearch measures what it should be

e.g. high validity means we can be sure the IV is the main/only thing affecting the DV

Types of Validity

• Internal validity: how sure we can be the IV affects the DV

• External Validity:how much does the study tell us about people real world behaviours

  • Populational validity: is the sample of ppts representative of the whole world

  • Ecological Validity: does the setting for the study reflect real life

Ethical Considerations: Informed Consent and Deception

• informed consent

  • at the beginning of a study ppts should be given comprehensive information concerning the nature and purpose of a study and their role in it

• Deception

  • Participants should not be Lied to or misled about the aims of a study

Ethical Considerations: Anonymity, Confidentiality and Protection from Harm

• anonymity and confidentiality

  • if a person’s privacy has been invaded their identity should be protected

• protection from harm

  • participants should not be placed at risk and their physical and physiological safety should be protected at all times

Sampling methods

• sampling is thr process of selecting a representative group for a study

• target populations is the group of induviduals from which the sample will be drawn from

Random Sampling

• all members of the target group have an equal chance of selection

  • +reasonable chance of acheiving a representative sample

  • - small minority groups in target group may distort results

  • - can be impractica to use a completeley random technique

Systematic sampling

• a systematic method is chosen for selection from a target group e.g. every fourth name

  • + assuming the list is randomised the method provides an unbiased representative sample

  • - if the list isnt randomised the method is biased

Stratified Sampling

• the sampler divides the target group into sections so the sample contains characteristics in a proportion representative of the target populations

  • + avoids misrepresentation

  • - takes more time and resources

Opportunity sampling

• participants who are acessible and willing to take part are targeted

  • + method is easy and inexpensive

  • - sample may not end up being representative

Quantative and Qualitative Data

• Quantative Data - data that involves words and numbers and has set answers

  • + easy to analyse

  • - lacks depth and detail

• Qualitative - data that starts out in words or pictures but can be turned into numbers

  • + has depth and detail

  • - hard to analyse

Primary and Secondary Data

• Primary Data - Data which has been collected firsthand by the researchers for the experiment

  • + data will suit the aims of the researcher

  • - takes more time and effort

• Secondary Data - Data that has already collected by someone else

  • + easy to access

  • - not tailored to the study

Experimental Design

The various ways in which participants can be organised into conditions in an experiment

Independent Groups Design

• ppts are allocated to one condition of the IV so there are separate groups for each condition

  • + can use same stimulus material in both groups

  • - unknown if induvidual differences are EVs

Repeated Measures

• ppts are involved in all conditions and their sets of data are compared. Half do one condition and then switch to the other

  • + measure for induvidual differences

  • - can’t use the same stimulus materials

  • - order effect

Matched Pairs

• ppts are allocated to one condition but they are matched to eachother on characteristics that may affect the DV e.g. age or sex

  • + comparing similar people without order effects

  • + can use same stimulus materials

  • - complicated to get matching people