Aims & hypotheses, Experimental design, Reliability & validity

What is a research aim?

A statement of a study’s purpose, stated beforehand to make it clear what the study investigates.

What is a null hypothesis?

A prediction that there will be no relationship or no difference between variables. It is assumed true during the study.

What is an alternative hypothesis?

A prediction that there is a relationship between variables. Accepted if the null hypothesis is rejected.

What is a directional hypothesis?

Predicts the direction of the difference or relationship (e.g., one group will do significantly better).

What is a non directional hypothesis?

Predicts a difference or relationship but does not specify the direction.

What is an independent variable?

The variable directly manipulated by the researcher.

What is a dependent variable?

The variable measured; it is affected by changes in the IV.

What is an extraneous variable?

Any variable (other than the IV) that could affect the DV.

When is an extraneous variable a confounding variable?

When it actually influences the DV.

What does operationalising variables mean?

Clearly defining how a variable is measured or manipulated.

Give an example of operationalising a variable.

Measuring “height” as distance in centimetres from the bottom to the top of the head.

What is the difference between an aim and a hypothesis?

The aim is the purpose of the study; the hypothesis is a testable prediction.

What is an independent groups design?

Different participants are used in each condition.

One advantage of independent groups design?

No order effects.

One disadvantage of independent groups design?

Participant variables may affect results.

What is repeated measures design?

The same participants take part in all conditions.

One advantage of repeated measures?

Fewer participants are needed.

One disadvantage of repeated measures?

Order effects may occur.

What is matched pairs design?

Participants are matched on key variables and assigned to conditions.

One advantage of matched pairs?

No order effects.

One disadvantage of matched pairs?

More participants needed.

Why should research be highly controlled?

To avoid the effects of extraneous variables.

What is counterbalancing?

Varying the order of conditions to control order effects.

What is random allocation?

Assigning participants to conditions by chance to avoid bias.

Why use standardised instructions?

So all participants receive the same instructions, reducing variability.

What is randomisation in experiments?

Presenting materials in a random order to avoid order effects.

What is a pilot study?

A small scale study to test procedures before the main study.

What is reliability?

The consistency of results.

What is internal reliability?

Consistency within a test.

How do you assess internal reliability?

Using the split half method (correlating scores on two halves of the test).

What is external reliability?

Consistency across time or occasions.

How is external reliability assessed?

Repeating the test with the same participants and correlating the scores.

What is inter observer reliability?

Consistency between different observers.

What is validity?

Whether a test measures what it claims to measure.

What is face validity?

Whether a test appears to measure what it should.

What is concurrent validity?

Comparing results with an existing valid measure.

What is ecological validity?

Whether results can be generalised to real life.

What is temporal validity?

Whether results can be generalised over time.

How can reliability and validity be improved?

Standardising research and operationalising variables clearly.

Why is operationalising variables important for validity?

It makes variables clear and specific so results are accurate.

When would you reject the null hypothesis?

If data shows a significant difference/relationship.

What’s the difference between directional and non directional hypotheses?

Directional predicts the direction of results; non directional does not.

Why run a pilot study?

To test procedures, check instructions, and spot problems early.

How does standardisation improve reliability and validity?

Reduces extraneous variables and ensures consistency.

Design an independent measures study to investigate the relationship between television viewing and memory.

[Requires full design – groups, IV, DV, controls, etc.]