research methods

Define aim

• a general statement of what the researcher intends to investigate- purpose of the study

Directional hypothesis

States the direction of the difference or relationship

Experimental methods

• a deliberate change that is made to an IV to measure the effect it has on the DV

• Lab, field, natural, quasi

Hypothesis meaning

A clear, precise, testable statement that states the relationship between variables to be investigated

Non-directional hypothesis

• does not state the direction of the difference or relationship

Operationalisation

Clearly defining variables in terms oh how they an be measured

Control group

A group of ppts who receive no treatment. acts as a baseline

Demand characteristics

When the ppt finds the aim of the study by finding clues. They may change their behaviour to fit what they think is expected.

Extraneous variables

Any variable other than the IV, that may affect the DV if not controlled

Investigator effects

how the investigators behaviour may effect the outcome of the study ( conscious or unconscious)

Standardisation

Using the same formalised procedures and instructions for all ppts in the study. So procedure doesn’t act as an extraneous variable

Experimental design

The different ways ppts can be organised in relation to the experimental conditions

Independent groups

When ppts are allocated to different groups. Each group represents one experimental condition

Repeated measures

When all ppts experience all conditions in the experiment

Matched pairs

Pairs of ppts are made dependent On different variables (eg IQ)

they then are split into different conditions

Counterbalancing

An attempt to control effects of order in repeated measures

Half experience in one order, the other in a different order

Weakness on independent groups

Less economical than repeated measures as you need twiceas many ppts to produce equivalent results

Strength of independent groups

Order effects are not a problem whereas they are a problem for repeated measures. Ppts are less likely to guess aims of the study

Weaknesses of repeated measures

Ppts have to do 2 tasks and the order may affect outcome. The first condition may have a continuing effect on the 2nd. So we use counterbalancing

Boredom or fatigue may cause deterioration in performance in the second task

Alternatively ppts performance may increase due to practice

Strengths of repeated measures

Ppt variables are controlled( higher validity) and fewer ppts are needed

Weakness of using matched pairs

Time consuming and expensive

Ppts can never be matched exactly- there will still be differences between them which may affect the DV

Laboratory experiments

A controlled environment where the experiment takes place. Strict control of extraneous variables

Strengths of lab experiments

• high control of extraneous variables , which ensures that the effect on the DV is directly a result of the IV

• Easier to replicate

Limitations of lab experiments

Lack generalisability as the lab does not reflect everyday life.

Unfamiliar conditions means ppts may behave unusually

Low external validity

Ppts know they are being tested so may act unnatural ( demand characteristics )

Field experiemnt

Bias in the context of sampling

When a certain groups are over or underrepresented. Limits the extent generalisations can be made.

Generalisation

The extent to which findings can be applied to the population

Random sample

Get a complete list of all members in the target population. Names are assigned numbers and are chosen at random

Systematic sampling

Every nth number is chosen

List is ordered and researcher starts from a random place.

Evaluate random sampling

Is potentially unbiased

Is time consuming and may not accurately represent the population.

Evaluate systematic sampling

Its objective and the researcher has no influence on who is chosen

Time consuming

Ppts may refuse to take part resulting in a volunteer sample and can result in a biased sample

Evaluate stratified sampling

Produces a representative sample of the population so that we can generalise

Cannot reflect all strata of the population so complete representation is not possible

Evaluate opportunity sampling

It's convenient, more economical as it saves time and money.

Strata isn't needed

Have 2 types of bias - unrepresentative sample so cannot be generalised

Researcher has control of ppts so may avoid ppl ( researcher bias.

Evaluate volunteer sampling

More economical

Ppts are more engaged an willing

Asking for volunteers may attract a certain de mographic