Psychology unit 1: Research methods

Independent Variable (IV)

The variable the researcher changes to see its effect.

Dependent Variable (DV)

The variable measured to see how it is affected by changes in the IV.

Hypothesis

It typically states the expected relationship between the independent and dependent variables.

Aim

A general statement of what the research is investigating.

Experimental Design

The way participants are organised into different conditions.

Repeated Measures Design

The same participants take part in all conditions.

Independent Groups Design

Different participants take part in different conditions.

Matched Pairs Design

Participants are paired based on similarities, one from each pair goes in different conditions.

Control Variable

Control variables help eliminate alternative explanations for the results by keeping certain factors constant throughout the experiment.

Extraneous Variable

A variable other than the IV that could affect the DV if not controlled

Confounding Variable

A variable that unintentionally affects the DV, making it hard to know if the IV caused the change.

Demand Characteristics

When participants guess the study’s aim and change their behaviour.

Investigator Effects

When the researcher's behaviour influences participants or results.

Randomisation

Using chance to decide the order of tasks or participants, reducing bias.

Standardisation

Keeping procedures identical for all participants.

Laboratory Experiment

Conducted in a controlled setting where variables are managed.

Field Experiment]

Done in a natural environment but the researcher still manipulates the IV.

Natural Experiment

The IV changes naturally; the researcher measures the effect.

Quasi-Experiment

The IV is based on existing characteristics like age or gender — it's not manipulated.

Population

The larger group the researcher is interested in.

Sample

A smaller group taken from the population to take part in the study.

Random Sampling

Everyone in the population has an equal chance of being selected.

Opportunity Sampling

Participants are selected because they are available at the time.

Volunteer (Self-selected) Sampling

Participants choose to take part, often through an advert.

Systematic Sampling

Selecting participants at fixed intervals from a list (e.g., every 3rd person).

Stratified Sampling

The sample reflects key sub-groups of the population in correct proportions.

Sampling Bias

When the sample does not represent the whole population fairly.

Quantitative Data

Data in numerical form, e.g., scores, measurements.

Qualitative Data

Data in words, e.g., descriptions, opinions.

Mean

The average score (add up all scores, divide by number of scores).

Median

The middle score when scores are arranged in order.

Mode

The most common score.

Range

The difference between the highest and lowest scores.

Validity

Whether the study measures what it is supposed to.

Internal Validity

How well the study controls variables to test its aim.

Ecological Validity

How well the results apply to real-life settings.

Reliability

Whether results are consistent and can be repeated.

Pilot Study

A small trial run to spot problems in the research.

Ethical Issues

Moral concerns about protecting participants' rights.

Informed Consent

, Participants agree to take part after being told all necessary information.

Deception

, Misleading participants about parts of the study (only allowed if necessary).

Right to Withdraw

Participants can leave the study at any time, for any reason.

Confidentiality

Keeping participants' personal details private.

Protection from Harm

Making sure participants are not physically or mentally harmed.