2024 Unit 1 Research Methods (AOS 3)

advantage of random sampling

Unbiased. All members of the target population have an equal chance of selection

Disadvantage of random sampling

may not be representative- accidentally biased with certain groups OVER or UNDER represented. Hard to get ENTIRE population.

stratified sampling

involves dividing the population into subgroups, and then randomly selecting participants from each subgroup in the proportion that they appear in the population

advantage of stratified sampling

Likely to be more representative than any other methods because there is a proportional and randomly selected representation of subgroups.

Disadvantage of stratified sampling

Very time-consuming to identify subgroups, then randomly select participants and contact them.

convenience sampling

using a sample of people who are readily available to participate

Advantage of convenience sampling

can reach a large number of respondents in a short time frame, easier

disadvantage of convenience sampling

not representative of the population

investigation aim

The purpose of the study written as a statement that includes the variables being studied.

investigation question

The question the study intends to solve, or what the researcher is trying to find out.

independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

dependent variable

The outcome factor; the variable that may change in response to manipulations of the independent variable.

Operationalising Variables

The process of devising a way of measuring a variable. It is a clear statement of what the variable is.

Hypothesis

a statement predicting the probable outcomes of an investigation. Needs to include population, IV, DV, comparison between the conditions

population of interest

the wider group of people that the researcher is interested in understanding

sample

the participants selected from the population, who participate in the investigation

representative sample

a sample that accurately reflects the characteristics of the population as a whole

random sampling

a sample that fairly represents a population because each member has an equal chance of inclusion

experimental group

In an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.

control group

In an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.

controlled variables

All those things that must be kept the same during the investigation to produce a valid, fair test.

extraneous variables

any variables other than the independent variable that seem likely to influence the dependent variable in a specific study. Should be controlled before an experiment is run.

Confounding Variables

a factor other than the independent variable that has produced an effect in an experiment.

extraneous v confounding variable

extraneous variables CAN affect results, confounding variables HAVE affected results.

controlled experiment

involves an experimental investigation of the relationship between one or more IVs and a DV; all other variables are controlled.

between subjects

Participants are either randomly allocated to the control or experimental condition.

advantage of between subjects

most time effective

disadvantage of between subjects

more participants are needed, less control over EV's

within subjects design

All participants in the sample are in both the control and experimental conditions

advantage of within subjects

no participant differences, fewer participants needed

disadvantage of within subjects

more time consuming, higher participant withdrawal rate

qualitative data

characteristics and descriptions. Can be in the form of words, photographs, videos, audio and other recordings that are not measured with a number.

quantitative data

measurable values and quantities and can be compared on a numerical scale. Can be in the form of measurements such as length, weight or time, or in the form of frequencies and tallies

measures of central tendency

mean, median, mode

mean

the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores. Vulnerable to outliers.

Median

the middle score in a distribution if ordered least to most; half the scores are above it and half are below it

mode

the most frequently occurring score(s) in a distribution

sources of error

measurement (random and systematic), random

random errors

occur because of random and inherently unpredictable events in the measurement process

systematic errors

Errors in measurement that are constant within a data set, sometimes caused by faulty equipment or bias

personal errors

Include mistakes, miscalculations and observer errors when conducting research.

repeatability

how close successive measurements of the same quantity are when carried out under the same conditions.

reproducibility

how close measurements of the same quantity are when carried out under different conditions

repeatability v reproducibility

repeatability is replicating the same experiment under similar conditions, whereas reproducibility is the extent to which a study's findings can be obtained by other researchers using different methods, settings, etc.

internal validity

refers to a study investigating what it sets out or claims to investigate. Internal validity can be affected by the appropriateness of the investigation design, sampling and allocation techniques, and the effect of extraneous and confounding variables

external validity

refers to whether the results of the research can be applied to similar individuals in a different setting

ethical principles

research merit, beneficience, justice, respect

research merit

research that is worthwhile and conducted appropriately to achieve the aims

Justice

have fair procedures been taken? Have the benefits of the research been shared widely?

beneficience

what are the likely benefits to participants or the wider community? Have the risks of harm to participants and to the community in general been minimised?

respect for human beings

Has the researcher taken into account the rights, beliefs, perceptions and cultural backgrounds of all their participants?

participant ethical guidelines

voluntary participation, deception, withdrawal rights, debriefing, informed consent, confidentiality

voluntary participation

Participation whereby participants agree to take part in an experiment free from pressure or fear of negative consequences.

deception

misleading participants about the true purpose of a study or the events that will actually transpire

withdrawal rights

A participant's right to withdraw from a study or research at any time without experiencing any negative consequences.

debriefing

the post-experimental explanation of a study, including its purpose and any deceptions, to its participants

informed consent

an ethical principle that research participants be told enough to enable them to choose whether they wish to participate

confidentiality

The researcher must not use or disclose private information for any purpose other than that for which it was given to them.