research methods

What is an independent variable (IV)?

The variable that is manipulated by the researcher to test its effect on the dependent variable.

What is a dependent variable (DV)?

The variable that is measured to see if it changes when the IV is manipulated.

What is operationalization?

The process of defining variables so they can be measured or manipulated in a clear, specific way.

What are the key differences between laboratory and field experiments?

Laboratory experiments offer high control but low ecological validity; field experiments offer better ecological validity but less control.

What is a natural experiment?

A study where the IV occurs naturally and cannot be manipulated by the researcher, but the effects are studied scientifically.

What is the difference between correlation and causation?

Correlation shows a relationship between variables but doesn't prove that one causes the other; causation demonstrates direct cause and effect.

What are the advantages and disadvantages of random sampling?

Advantages: Reduces bias, every member has equal chance. Disadvantages: Time-consuming, may not represent all subgroups.

What is stratified sampling?

A method where the population is divided into subgroups and participants are randomly selected from each group proportionally.

How does opportunity sampling differ from random sampling?

Opportunity sampling selects participants who are easily available, while random sampling gives every member an equal chance.

What are the main features of an independent groups design?

Different participants in each condition, no order effects, but possible individual differences between groups.

What are the advantages of a repeated measures design?

Same participants in all conditions, no individual differences between groups, but possible order effects.

What is a matched pairs design?

Participants are matched on key variables and then split between conditions, controlling for individual differences.

What is the difference between quantitative and qualitative data?

Quantitative data is numerical and can be measured statistically; qualitative data is descriptive and focuses on meanings.

What are the three measures of central tendency?

Mean, Median, Mode.

What is standard deviation?

A measure of spread that shows how much values typically differ from the mean.

What is informed consent?

Participants must be told about the nature of the study and agree to participate, understanding their rights.

What is debriefing?

The process of explaining the full nature of the study to participants after it ends.

When might deception be justified in psychological research?

When knowledge of the true aims would affect behavior and when potential benefits outweigh costs.

What is the difference between reliability and validity?

Reliability refers to consistency of results; validity refers to whether the study measures what it aims to measure.

What factors can threaten internal validity?

Extraneous variables, demand characteristics, investigator effects, participant bias.

How can ecological validity be improved?

By conducting research in natural settings and using real-life tasks.

What makes a good research aim?

It should be clear, specific, measurable, and achievable.

What is the difference between directional and non-directional hypotheses?

A directional hypothesis predicts the specific direction of the relationship; a non-directional hypothesis only predicts that a relationship exists.

What is the purpose of a null hypothesis?

The null hypothesis states there is no significant relationship between variables, serving as a baseline to test against.

What are three main benefits of conducting a pilot study?

Identifies potential problems, tests participant understanding, estimates required time and resources.

How should results from a pilot study be used?

To refine methodology, adjust timings, clarify instructions, and modify materials.

Why is a pilot study important for validity?

It helps identify and eliminate confounding variables.

What is standardisation and why is it important?

Keeping all procedures constant to reduce confounding variables and increase reliability.

How does random allocation differ from randomisation?

Random allocation refers specifically to assigning participants to conditions randomly.

What is counterbalancing and when is it used?

Counterbalancing involves rotating the order of conditions to control for order effects.

What are the key characteristics of a normal distribution?

Bell-shaped, symmetrical, with 68% within 1 SD, 95% within 2 SD, and 99.7% within 3 SD.

In a positively skewed distribution, what is the relationship between mean, median, and mode?

Mean > Median > Mode.

What percentage of data falls within two standard deviations of the mean in a normal distribution?

95% of all data.

What are the advantages and disadvantages of using the mean?

Advantages: uses all data points; Disadvantages: affected by extreme scores.

When is the median most appropriate to use?

With skewed data or when there are extreme scores.

What makes the mode useful or limited as a measure of central tendency?

Useful for categorical data; limited if there are multiple modes.

Why might you need to calculate all three measures of central tendency for a dataset?

Different measures provide different insights into the distribution shape.