science inquiry Psych

types of sampling

convenience, random, stratified

convenience sampling

quick easy select participants based on accessibility

random sampling

ensures every member of a population has an equal chance of being selected

stratified sampling

breaking population into groups based on characteristics

reaserch designs

experimental, observational, case study, correlational, longitudinal, cross sectional

methods to sample populations

Convince, snowballing, random, stratified

ways to minimise effects of extraneous and confounding variables

random allocation of participants, single-blind procedure, standardisation of procedures and instructions

experimental research

using scientific method to systematically study the effect of an independent variable of a dependent (can identify cause effect relationship)

two groups in experimental research

experimental group and control group

advantages of experimental research

identifies cause and effect relationship, experiment can be repeated multiple times to check reliability

disadvantages of experimental research

the artificiality of the study (lab conditions), demand characteristics or experimenter effects my bias results and become confounding variables

control group

a group where independent variable is absent (provides a comparison)

random allocation

participants are put in groups where every member has same probability of being in either group

advantages of random allocation

reduces bias, limits effect of participant variables (extraneous variables that impact how participants respond)

disadvantages of random allocation

still possible for there to be bias

non random allocation

participants put in groups based on different criteria

independent measures

different participants are used in each condition of the independent variable, should be done with random allocation

advantages of independent measures

avoids order effects because people only participate in one condition (when someone does multiple they may get tired by the second one which would alter results)

disadvantages of independent measures

more people are needed, differences between participants may effect results

matched groups design

uses different but similar participants in each condition in terms of any important characteristics which might effect performance (gender, age, intelligence)

advantages of matched groups

reduced effect of participant variables because they are paired with people with similar characteristics, avoids order effects, so counterbalancing is not necessary

disadvantages of matched groups

in one participant drops out you loose both participants set of data, very time consuming, impossible to match people exactly.

repeated measures

same participants take part in each condition of the independent variable so each involves the same group of participants

advantages of repeated measures

individual differences are reduced

disadvantages of repeated measures

may be order effects (order of effects may have effect on behaviour/performance of participants)

non-experimental research

where an independent variable is unable to be manipulated (no cause and effect)

advantages of non-experimental research

provides rich detailed information, may be more ethical particularly when manipulating variables may cause harm

disadvantages of non-experimental research

cannot identify cause and effect (requires further research), difficult to control for extraneous variables, expert knowledge often required to analyse data

observational research design

researches set up study, they watch and observe effects

advantages of observational research design

reduces bias,

disadvantages of observational research design

difficult to measure strength of attitude as data collected is limited, not accurate measure as attitudes and behaviour are often inconstant

case study

intensive examination of the behaviour and mental processes associated with specific person

advantages of case study

useful when larger numbers of participants are unavailable, good when it would otherwise be unethical

disadvantages of case study

can be misleading(subject may be atypical), uncontrolled variables limits conclusions that can be drawn, often poor reliability correlational studies

correlational design

researchers look for a relationship between to or more behavioural variables and try to find the strength between them

advantages of correlation research

can study variables that are measurable but not manipulatable (more ethical), can demonstrate presence or absence of a relationship for a further study

disadvantages of correlation research

correlation does not equal causation

longitudinal design

involves following a set of participants over long period of time to collect observational data

advantages of longitudinal

looks at direct changes in participants(very reliable), investigate ho condition progress

disadvantages of longitudinal

time consuming, expensive, higher chance of participants dropping out

cross sectional design

compares data collected at the same point in time from people of different groups

advantages of cross sectional design

inexpensive, less time consuming than longitudinal, less chance of participants dropping out

disadvantages of cross sectional design

large sample needed, cohort effect(differences in life experiences), participant variables influence results

participants

people who provide data in psychological studies

population

entire group of research interest from which a sample is drawn and research findings can be generalised

sample

smaller group of research participants selected from larger population

non probability sampling

non randomised (not every participant has opportunity to be includes in the study)

convenience sampling

chosen because easily accessible to researcher

application of convenience sampling

medical research studies

strengths of convenience sampling

least expensive, least time-consuming, most convenient

limitation of convenience sampling

It is subject to bias and may not represent the population well.

snowball sampling

researcher interviews individuals of interests who then provide names of other people of interest in same population

application of snowball sampling

population of interest is hard to find

strengths of snowball sampling

convenient voluntary participation

limitations of snowball sampling

Likely to be biased because participants know each other

Ethical issues are difficult to maintain since participants know each other

random sampling

every member of population has an equal chance of being selected (names randomly selected)

application of random sampling

blind experiment

strengths of random sampling

high generalisability , reduced bias

limitations of random sampling

impractical-not all members of a population will be willing to take part

not representative-unbiased selection doesn't guarantee an representative sample

stratified sampling

used when research requires sample to contain the same proportions of participants as found in the population

application of stratified sampling

evaluate data from different subgroups

strengths of stratified sampling

representative, high generalisablity, unbiased

limitations of stratified sampling

time consuming potential misclassification

two types of validity

internal and external

internal validity

how accurately research establishes a causal relationship between independent and dependent variables, minimising the influence of other factors or variables

external validity

how much the findings of a study can be generalised or applied to other situations, beyond the specific context of the research

random allocation application

randomly select who receives treatment

strengths of random allocation

generalisability

limitations of random allocation

risks imbalance

protection from harm (beneficence)

must be protected from both physical and psychological harm (some allowed in certain cases where the harm is minimal and the study benefits society)

informed consent

voluntary agreement to participate in a procedure on the basis of their understanding of its nature (benefits and potential risks)

deception

deliberately misleading or withholding information from participants to obtain more accurate results

demand characteristics

when a participants behaviour is altered by the knowledge of the aim of the study

privacy

participants right to control the amount of information they provide about themselves

confidentiality

right of participants to have any information they tell researcher kept private

voluntary participation

participants must agree to participate of their own free will and fee of any other influence

right to withdraw

participants must be aware prior to the star of the research that they can leave the study at any stage without penalty or punishment and ability to remove results

3 r's

refinement, reduction, replacement

reduction

reduce number of animals used to as few as possible

replacement

use alternative non animal methods whenever available

refinement

as little pain and stress as possible experienced by animals

placebo effect

change in dependent variable because they believe they are getting the intervention not because they actually are

use of placebo

unaware of whether they got placebo or not

experimenter effect

experimenter behaviours and expectations of researcher that may effects the results

qualitative collection methods

interviews, individual, open-ended survey

quantitative subjective methods

checklists, rating scales, likest scales

quantitative objective methods

heart rate, breathing rate, galvanic skin response

difference between subjective and objective

Subjective statements based on personal opinions, or interpretations

what is an objective statement

objective statements are based on facts and verifiable data, free from personal bias

Test-retest reliability

a method for determining the reliability of a test by comparing a test taker's scores on the same test taken on separate occasions

inter test reliability

consistency across judges/two or more researchers get the same results

degree of agreement among different individuals when they rate, score, or assess the same phenomenon or item

reduction

reduce number of animals used to as few as possible

replacement

to use alternative non-animal methods whenever they are available

refinement

refine all procedures to ensure that as little pain and stress as possible is experienced by animals

Central nervous system parts

Brain and spinal chord

Peripheral nervous system parts

Somatic and autonomic

parts of the autonomic nervous system

Sympathetic and parasympathetic