RM PT1

Research Question

An idea you want to test- answer via experiment

Aim

A general, testable statement that describes the purpose of your investigation. “To investigate…”

Hypothesis

The prediction about what you will find- needs to be a precise testable statement

What are the 2 types of hypotheses?

Null & alternative hypothesis

Alternative hypothesis

states there will be a change

Null hypothesis

States there will be no change

What are the 2 types of alternative hypotheses?

Directional and non-directional

Directional hypothesis

Where you specify the direction of difference

Non-directional hypothesis

Where you state there will be a difference- not predicting what the difference will be

Independent variable (IV)

The variable the researcher manipulates- changes

Dependant variable (DV)

The variable the researcher measures

Operationalisation

Clearly defining variables in a way that they can be measured

Define extraneous variables

Extra unwanted variables that could have an affect on the DV & is not the IV

Define confounding variables

Extra unwanted variables that definitely have affected the DV & is not the IV - reduces validity

What are 2 types of extraneous variables?

Participant variables & situational variables

Give some participant variables examples.

• Age

• Participant motivation

• Intelligence

• Concentration levels

• Gender

• Demand characteristics

Give some situational variables examples.

• Noise

• Weather

• Temperature

• Times of day

• Instructions- researcher bias

Define researcher bias.

Term used to describe subtle cues or signals from an experimental that affect the research results

Define demand characteristics.

Features of an experiment that allow participants to work out the aim &/or the hypothesis- participants may change behaviour- interferes with the study

What are ways to control EVs to prevent them turning into CVs?

• randomisation

• standardisation- standardise instructions & standardised procedures

What is standardised procedures and instructions?

• procedures- keeping everything & method the same, except the IV so more certainty that the IV affects the DV

• instructions- pre-made set of instructions that are read out to all participants

  • reduces chance of demand characteristics because no subtle cues or hints are given

Define experimental design.

The different ways in which the testing of participants can be organised in relation to the experimental conditions.

Define independant groups design.

Ppts are allocated to different groups where each group represents one experimental condition.

Define repeated measures.

All participants take part in all conditions of the experiment.

Define matched pairs.

Pairs of ppts are matched on a variable that may affect the DV. One member of the pair is assigned to Condition A and one member to Condition B.

Define random allocation.

An attempt to control for ppt variables in an independent groups design which ensures that each ppt has the same chance of being in one condition than any other.

Define counterbalancing.

An attempt to control for the effects of order in a repeated measures design: half the ppts experience the conditions in one order and the other half in the opposite order.

What is a weakness of independent groups design?

Weakness- participant variables may affect study

Strength for independent groups design.

-No order effects

What is a strength of repeated measures?

Strength- fewer ppts needed- ecological, ppt variables are controlled

Weakness- order effects

Weakness of repeated measures.

Order effects

What is a strength and weakness of matched pairs design?

Strength- ppt variables are controlled

Weakness-time consuming and expensive, less economical than other designs

What are the 4 types of experimental designs?

• lab experiments

• field experiments

• natural experiments

• quasi- experiments

Define lab experiment.

Takes place in a controlled environment where the researcher manipulates the IV and records the effect on DV, whilst maintaining strict control of EVs

Describe a field experiment.

Takes place in a natural setting within which the researcher manipulates the IV and records the effect on the DV.

Describe a natural experiment.

An experiment where the change in the IV is not brought about by the researcher but would have happened even if the researcher was not there. The researcher records the effect on the DV.

Describe a quasi experiment.

A study that is almost an experiment but lacks key ingredients – the IV has not been determined by anyone (the researcher or any other person) – the variables simply exist, such as being old or young.

What is a strength and weakness of lab experiments?

-strength- high control of EVs

-strength- replication is possible because environment is controlled

-weakness- may lack generalisability because lab experiments may be artificial

-weakness- participants may show demand characteristics

What is a strength and weakness of Field experiments?

-strength- higher realism than lab

-weakness- less control on EVs

What is a strength and weakness of natural experiments?

What are the 5 types of sampling?

• volunteer sampling

• random sampling

• stratified sampling

• systematic sampling

• oppurtunity sampling

What is volunteer sampling?

Participants become part of study because they volunteer in response to an advert

What is a weakness of volunteer sample?

One weakness is that it only attracts a certain type of sample, people with a certain characteristic, making the results the results not generalisable to the wider population

What is random sampling?

Every member of target population has equal chance of being chosen- computer randomiser

What is a strength and weakness of random sampling?

Strength- each member of target population has same chance of being selected- best chance of obtaining unbiased sample

Weakness- sample is not always representative of population

What is stratified sampling?

Involves classifying population into categories and then choosing sample consisting of pots of each category in same proportion as they are in population

What is a strength and weakness of stratified sampling?

Strength- most representative sampling method

Weakness- very time consuming and identifying members of all subgroups can be difficult

What is systematic sampling?

Involves taking every nth person from a list to create a sample

What is a strength and weakness of systematic sampling?

Strength- allows sample to be evenly spread over entire target population

Weakness- very time consuming or impractical for very large target population

What is oppurtunity sampling?

Takes people who are available and willing to take part- reaercher approaches them

What is a strength and weakness of opportunity sample?

Strength- quick and convenient- most economical, most often used

Weakness- unrepresentative of target population as only relies on people wanting to take part