Psychology Unit 2 section B

Random Sampling

participants are selected using a random technique so that every member of the target population has an equal chance of getting selected. For example names pulled out of a hat.

Volunteer Sampling

participants themselves come forward to take part. For example a newspaper advert can be published and people would choose to participate in the study.

Opportunity sampling

people who are available at the time are selected. For example in a coffee shop, between 10-11am.

Quata Sampling

The target population is divided into subgroups like age,sex and ethnicity. Participants are selected according to their frequency in the population, opportunistically.

Stratified

The target population is divided into subgroups like age,sex and ethnicity. Participants are selected according to their frequency in the population, random sampling is used.

Systematic a system used. After the first participant is selected every nth person is selected.

a system is used. After the first participant is selected every nth person is selected.

Snowball Sampling

initially selected participants recruit further participants. The sample, therefore, grows like a snowball.

Null Hypothesis

There will be no significant difference ………… . Any difference will be due to chance.

Operationalisation

defining what we are testing so it can be measured objectvely.

Ethical Issues

Confidentiality, Right to withdraw, Deception, Risk of stress, Risk of values/beliefs, Valid consent,

Animal ethics

Home office established the 3R rule: reduce, replace, refine

Lab experiment

takes place in an artificial environment and uses standardised procedures. Researcher manipulates the IV while controlling the other variables.

• there is a high level of control so the researcher can control extranous variables and therefore a clear cause and effect can be established. This improves internal validity.

• Due to artificial environment participants’ behavior may not be natural. This lowers the ecological validity as the results cannot be generalised to real life.

Field experiment

An experiment that takes place in a natural environment. Experimenter still manipulates the IV but has less control over extraneous variables such as noise.

• It takes place in a natural environment so it is less likely to produce artificial behavior. This increases ecological validity as results can be generalised to real life.

• Extraneous variables are more difficult to control because it takes place in a natural environment. Factors such as noise might have an effect on dependent variable which lowers internal validity.

Quasi Experiment

The researcher does not randomly allocate conditions to participants as the IV is an aspect of the participants. For example when the IV is gender, a researcher cannot randomly allocate the roles of man and woman.

• The researcher looks at preexisting conditions. This allows them to conduct researchs that would not be possible otherwise. This makes it an ethical choice for a method.

• Independent variable is not randomly allocated so we cannot be sure of the direct cause of the IV on the DV. This makes it low in internal validity compared to lab experiments.

Natural experiment

The researcher does not randomly allocate conditions to participants as the IV is an aspect of the participants. The participants have gone through an event that has not been planned by the researcher. An example would be a study looking at the effect of early childhood seperation.

• It allows the research to be conducted on topics that IV could not have been manipulated due to ethical reasons. This makes it an ethical choice as a method.

• Independent variable is not randomly allocated so we cannot be sure of the direct cause of the IV on the DV. This makes it low in internal validity compared to lab experiments.

Participant observation

Where the observer joins the group and observes the behaviour of that group. It often takes place in natural environments and uses checklists to record behaviours seen.

• It is more likely to be accurate as the observer is observing from within the group so is less likely to miss behaviors compared t non participant observations. This increases internal validity.

• Researcher bias may occur which would make the results invalid. The observer may be more likely to see and record behaviours that record their hypothesis. This lowers internal validity.

Non participant observation

where observer does not join the group and simply watches the group from a distance without interfering in any way. For example watching students in the canteen by CCTV cameras.

• Researcher is not involved with the group therefore they can be more objective when observing as they have not formed any kind of relationship with the participants. This would make the data more internally valid compared to participant observations.

• Observer bias may exist, especially if the categories are not operationalized. The researcher would be more likely to recored behaviours that fit their hypothesis. This lowers internal validity of the research.

Content Analysis

It is a form of indirect observation. The researcher looks at aretfact such as book and magazines, and analyses the information in a systematic way. For example tallying the number of times female authors are cited.

• it has high ecological validity as the artifacts are found from the real world.

• Its reliability can be checked. For example rewatching or rereading the artifacts to analyze them again.

• It is prone to researcher bias as the researcher may only record things that fit their hypothesis. This lowers internal validity.

Questionnaire

consists of a list of written questions and is a method of collecting data.

• they are standardized as the same questions are asked in the sameorder to all participants. This improves reliability.

• response rates can be low. For example, individuals often receive questionnaires in the post and do not have the time or willingness to complete them. Therefore, only a small proportion of the questionnaires are completed which, may mean the findings are not valid as they have not been completed by a large enough sample.

Structured interview

Structured interviews ask a set of standardised questions to all participants, known as an interviewschedule. No additional questions are asked.

• easy to replicate as a fixed set of questions are asked to all participants. This means that there is consistency in measuring the behaviour of interest, improving internal reliability.

• are not flexible. This means spontaneous questions cannot be asked as an interview schedule must be followed exactly. This can lead to areduction in the quality of data gained, compared to a semi-structured interview, loweringinternal validity.

Semi structured interview

may include some specific questions which must be asked but overall the styleis more flexible than a structured interview. This allows the researcher to ask follow-up (spontaneous) questions

Case study

A detailed study of a single individual, institution or event. Case studies are generally longitudinal (take place over a long period of time) and may involve many different data sources such as interviews, questionnaires and observations (is holistic).

• the researcher can gain indepth data to help understand the behaviour of one individual. This can lead to very rich, qualitative data on one individual improving internal validity.

• it is difficult the findings beyond the individual/group being studied. This lowers external validity.