Scientific processes

aim

a general statement that describes the purpose of an investigation

hypothesis

a testable statement predicting the outcome at the start of a study

directional hypothesis

makes a clear anticipation of an experimental outcome

non directional hypothesis

states that there is a difference between conditions and groups but the nature is not specified

directional hypothesis is aka

one tailed

non directional hypothesis is aka

two tailed

null hypothesis

predicts no difference between variables

operationalisation of variables

clearly defining variables in terms of how they are being measured

extraneous variable

any other variable that is not the iv and affects the dv

extraneous variable example

age of participants, lighting in a lab

cofounding variables

any other variable that is not the iv and affects the dv that change systematically with the iv

demand characteristics

when participants guess the aim of the study and act accordingly

please u effect

participants act in a way to please the researcher

screw u effect

participants intentionally under perform to sabotage the study affecting validity

investigator effects

undesired influence of the investigator on the outcome of the research

eg of investigator effects

design of study, selection of participants

minimising investigator effects

randomisation ( reduces unconscious bias)

standardisation

using the exact same procedures and instructions for each participant

4 types of experiment

lab, natural, field , quasi

strengths of lab experiement

high internal validity, easy to replicate

limitations of lab experiment

may lack ecological validity, risk of demand characteristics

field experiement

the iv is manipulated in a natural setting

strength of field experiment

high mundane realism, reduces demand characteristics

limitations of field experiment

loss of control of extraneous variables, ethical issues- consent

natural experiments

researcher has no control over the iv

strengths of natural experiments

high external validity

limitation of natural experiment

natural events are rare, difficult to identify causation

quasi experiments

has an iv based on existing differences between people eg age

strengths of quasi experiment

easy to replicte

limitation of quasi experiment

extraneous variables, hard to infer causation

internal validity

the degree of confidence that the relationship being tested is not influenced by other factors

external validity

applying the conclusions of a study to context outside the study

mundane realism

how similar a study is to real life situations

experimental design

the way in which participants are arranged in an experiment

3 types of experimental design

independent groups
repeated measures
matched pairs

independent groups

when two seperate groups of participants experience two different conditions of the experiment

strengths of independent groups

reduces demand characteristics, order effects can be prevented

repeated measures

all participants experience both conditions of the experiment

strengths of repeated measures

no participant variables, cheap as you dont need many participants

weaknesses of repeated measures

order effects, demand characteristics

weakness of independent groups

participant variables, expensive , time consuming

matched pairs

participants are put into conditions based on similarity of backgrounds relevant to study

strengths of matched pairs

reduces participant variables

weakness of matched pairs

time consuming, expensive, cant fully eliminate individual differences

participant variables

individual differences between participants that could affect the dv

order effects

when a participant’s performance in one condition is affected by having already taken part in another condition.

eg of order effects

fatigue, practive

counterbalancing

reduces order effects by half or participants doing condition a then b then other doing b then a

situational variables

features of the situation that could affect the dv

eg of situational variables

weather, noise, temperature

social desirability

when participants present themselves in a favourable light

3 types of investigator effects

expectancy effect, unconscious bias and leading questions

expectancy effect

the researchers expectations of the outcome influence the participants behaviour or recording of results

unconscious bias

subjective decisions and judgements made by the researcher

leading questions

asking questions that guide participants to answer

in specific ways

self report

any method in which a person is asked to state

or explain their own feelings and opinions on a given

topic.

questionnaires

a set of written questions to assess a person’s thoughts/experiences

open questions

no fixed range of answers, can answer freely

closed questions

fixed responses, choose from given options available

open questions give

qualitative data

closed questions give

quantitative data

strengths of questionnaires

cost effective, data is easy to analyse

weakness of questionnaires

social desirability, response bias

likert scale

indicates respondents level of agreement

rating scale

respondents identify a value that represents their strength of feeling

overuse of jargon

overuse of technical terms familiar to certain people

questions should avoid

emotive language

double barrelled questions

contains two separate questions

double negatives

contain two negatives causing confusion

population

a group of people from whom the sample is drawn

sample

group of individuals who take part in an investigation

random sampling

all members of population have an equal chance of being selected

strengths of random sampling

no researcher bias, high internal validity

disadvantages of random sampling

time consuming, volunteer bias

volunteer bias

when volunteers refuse to take part

systematic sampling

where every nth member is selected from the sample

strengths of systematic sampling

no researcher bias

disadvantages of systematic sampling

time consuming

strattfied sampling

when the composition of sample is divided into strata based on characteristics

advantages of stratified sampling

no researcher bias, representative of data

disadvantages of stratified sampling

time consuming, not fully representative

opportunity sampling

participants are selected by who is nearby and available

strengths of opportunity sampling

efficient, cheap

disadvantages of opportunity sampling

unrepresentative of population, researcher bias

volunteer sampling

when participants select themselves to be apart of sample

advantages of volunteer sampling

quick, more likely to cooperate

disadvantages of volunteer sampling

volunteer bias, motivations

Correlation

the strength and direction of an association between two or more variables

positive correlation

when one varibale increases the other increases

negative correlation

when one variable increases the other decreases

zero correlation

no relationship between variables

strengths of correlation

Cost effective

Correlation does not infer

causation

observation

when the researchers watch behaviour without inferring or manipulating the situation

8 types of observation

Naturalistic

Controlled

Covert

Overt

Participant

Non participant

Structured

Unstructured

Naturalistic

observation takes place in a realistic setting

Strengths of naturalistic

High ecological validity

Weakness of naturalistic

extraneous variables

hard to replicate

Controlled observations

some variables of the observation are controlled

strengths of controlled observation

easy to replicate