Research Methods - P2 Flashcards
What is an Experimental method? - AO1
- Give examples of types
Involves the manipulation of an independent variable (IV) to measure the effect on the dependent variable (DV)
- experiments may be laboratory, field, natural or quasi
What is an Aim? - AO1
A general statement of what the researcher intends to investigate, the purpose of the study
What is a Hypothesis? - AO1
A clear, precise, testable statement that states the relationship between the variables to be investigated - stated at the outset (start) of any study
What is a Directional hypothesis? - AO1
States the direction of the difference or relationship
- need to include the measurements, time of day, etc.
–> E.g.
‘people who drink water are less talkative than people who drink fizzy drinks’
What is a Non-directional hypothesis? - AO1
Does not state the direction of the difference or relationship
–> E.g.
‘there is a difference in talkativeness between those who drink water and those who drink fizzy drinks’
What are Variables? - AO1
Any ‘thing’ that can vary or change within an investigation
Variables are generally used in experiments to determine if changes in one thing result in changes to another
Independent Variable (IV) definition - AO1
Some aspect of the experimental situation that is manipulated by researcher - or changes naturally - so the effect on the DV can be measured
Dependent Variable (DV) definition - AO1
The variable that is measured by researcher
any effect on the DV should be caused by the effect in the IV
What is Operationalisation? - AO1
Clearly defining variables in terms of how they can be measured
What are Extraneous Variables (EV)? - AO1
Any variable, other than the IV, that may affect the DV if not controlled
- EV’s are essentially nuisance variables that do not vary systematically with the IV
- something that investigators try best to avoid/plan beforehand to avoid
What are Confounding Variables (CV)? - AO1
A kind of EV but the key feature is that CV’s varies systematically with the IV
Therefore we can’t tell if any change in the DV is due to the IV ore the confounding variable
- something that is out of the control of investigator, e.g. amount of sleep
What are Demand Characteristics? - AO1
Any cue from the researcher or research situation that may be interpreted by participants as revealing the purpose of an investigation
- This may lead to a participant changing their behaviour within the research situation
What are Investigator Effects? - AO1
Any effect of investigator’s outcome (conscious or unconscious) on the research outcome (the DV)
This may include everything from the design of the study to selection of, and interaction with, participants during the research process
What is Randomisation? - AO1
The use of chance methods to control for the effects of bias when designing materials and deciding the order of experimental conditions
What is Standardisation? - AO1
Using exactly the same formalised procedures and instructions for all participants in a research study
What are pilot studies? - AO1
Small-scale trial run of an investigation to ‘road-test’ procedures, so that research design can be modified.
What are control groups and conditions? - AO1
- Control groups, independent groups, design or control conditions, repeated measures design are used to set comparison.
- They act as a ‘baseline’ and help establish causation.
What is a single blind and double-blind? - AO1
- Single blind - A participant doesn’t know the aims of the study, so that demand characteristics are reduced.
- Double blind - both participant and researcher don’t know the aims of the study to reduce demand characteristics and investigator effects.
What is Experimental design? - AO1
The different ways in which the participants can be organised in relation to the experimental design
What is Independent Groups design? - AO1
Participants are allocated to different groups where each group represents one experimental condition
What is Repeated measures Design? - AO1
All participants take part in all conditions
What is Matched Pair Design? - AO1
Pairs of participants are first matched on some variable(s) that may affect the dependent variable. Then one member of the pair is assigned to condition A and the other to condition B
What is Random allocation? - AO1
An attempt to control for participant variables in an independent groups design which ensures that each participant has the same chance of being in one condition as any other
What is Counterbalancing? - AO1
An attempt to control for the effects of order in a repeated measures design: half the participants experience the conditions in one order, and the other half in the opposite order
STRENGTHS & LIMITATIONS of the independent groups design - AO3
How do you overcome limitations?
S - No order effects
S- Participants are also less likely to guess their aims.
L- The participants who occupy the different groups aren’t the same in terms of participant variables
L- Twice as many participants are used, which is time consuming.
L- Differences could lead to confounding variables, which decreases accuracy.
Radom allocation would help overcome the limits
STRENGTHS & LIMITATIONS of the Repeated Measures design - AO3
How do you overcome limitations?
S- Participant variables are controlled, therefore higher validity
S- fewer participants are needed, therefore less time spent recruiting them
L- Participants have to do the two tasks and the order of order of tasks may have a significant effect: Order effects
Counterbalancing, so switching order
STRENGTHS & LIMITATIONS of the Matched Pairs design - AO3
How do you overcome limitations?
S- Single condition, so order effects and demand characteristics are less common
L- participants can never be matched exactly
L- Time consuming and expensive
L- Order effects
Using identical twins can decrease this
What are the four different types of experiments? - AO1
- Laboratory experiment.
- Field experiment.
- Natural experiment.
- Quasi-experiment.
What is a laboratory experiment? - AO1
- A controlled environment where extraneous and confounding variables can be regulated.
- Participants go to the researcher.
- The IV is manipulated and the effect on the DV is recorded.
Explain how EVs + CVs can be controlled in a laboratory experiment. - AO3
- STRENGTH
- This means that the effect of EVsand CVs on the DV can be minimised.
- Cause + effect between IV and DV can be demonstrated (high internal validity)
Explain how EVs + CVs can be more easily replicated in a laboratory experiment. - AO3
- STRENGTH
- Greater control means less chance that new EVs introduced.
- This means that findings can be confirmed, supporting their validity
How may laboratory experiments lack generalisability? - AO3
- LIMITATION
- The controlled lab environment may be rather artificial + participants are aware they are being studied
- Thus behaviour may not be ‘natural’ and can’t be generalised to everyday life (low external validity)
How may demand characteristics be a problem in laboratory experiments? - AO3
- LIMITATION
- These are cues in the experimental situation that invite a particular response from participants
- The findings may be explained by these cues rather than the effect of the IV (low internal validity)
What is a field experiment? - AO1
- A natural setting
- Researcher goes to participants.
- The IV is manipulated and the effect on the DV is recorded.
What makes a field experiment a more natural environment? - AO3
- Participants more comfortable and behaviour more authentic.
- Results may be more generalisable to everyday life.
How is it a positive that participants are unaware of being studied in field experiments? - AO3
- They are more likely to behave as they normally do, so the findings can be generalised.
- The study has greater external validity.
More difficult to control CVs/EVs in field experiments? - AO3
- Observed changes in the DV may not be due to the IV, but to CVs/EVs instead
- It is more difficult to establish cause and effect than in the lab.
What are the ethical issues of field experiments? - AO3
- Participants in a field experiment may not have given informed consent.
- This is an invasion of participants’ privacy, which raises ethical issues.
What is a natural experiment? - AO1
- The experimenter does not manipulate the IV - It does change, but the change is made by the experimenter - someone or something else causes the IV to vary.
- DV may be naturally occurring or maybe devised by the experimenter and measured in the field or a lab
How is a natural experiment possibly the only practical/ethical option? - AO3
- STRENGTH
- It may be unethical to manipulate the IV e.g. studying the effects of institutionalisation on children.
- A natural experiment may be the only way causal research can be done for such topics.
How does a natural experiment have greater external validity? - AO3
- STRENGTH
- Natural experiments involve real-world issues, such as the effect of a natural disaster on stress levels.
- This means the findings are more relevant to real experiences.
How is natural events occurring rarely a limitation to natural experiments? - AO3
- LIMITATION
- Any natural events are one-offs and this reduces the opportunity for research.
- This may limit the scope for generalising findings to other similar situations.
Why is it a limitation that participants are not randomly allocated in natural experiments? - AO3
- LIMITATION
- The experimenter has no control over which participants are placed in which condition, as the IV is pre-existing.
- May result in CVs that aren’t controlled. e.g. Romanian orphans adopted early May also be the friendly ones.
What is a quasi-experiment? - AO1
- IV is based on a pre-existing difference between people, e.g. age or gender. No one has manipulated this variable, it simply just exists
- DV may be naturally occurring (e.g. exam results) or may be devised by the experimenter + naturally measured in the field or a lab
How is there often high control in quasi-experiments? - AO3
- STRENGTH
- Often carried out under controlled conditions and therefore shares some of the strengths of lab experiments.
- This means, for example, replication is possible.
In quasi-experiments, how can comparisons be made between people? - AO3
- STRENGTH
- In a quasi-experiment the IV is a difference between people, e.g. people with and without autism.
- This means that comparisons between different types of people can be made.
How is it a limitation that participants aren’t randomly allocated in quasi-experiments? - AO3
- LIMITATION
- The experimenter has no control over which participants are placed in which condition, as the IV is pre-existing.
- Participant variables may have caused the change in the DV acting as a CV.
How are causal relationships not demonstrated in quasi-experiments? - AO3
- LIMITATION
- As with a natural experiment, the researcher does not manipulate/control the experiment.
- We cannot say for certain that any change in the DV was due to the IV.
What are the five different sampling methods? - AO1
- Random sample.
- Systematic sample.
- Stratified sample.
- Opportunity sample.
- Volunteer sample.
What is a population? - AO1
The large group of people that a researcher is interested in studying. For example, college students from the Northwest.
What is a sample? - AO1
It is usually not possible to include all members of the population in the study, so a smaller group is selected - the sample.
What is generalisation? - AO1
The sample that is drawn should be representative of the population so generalisations can be made.
What is bias? - AO1
Most samples are biassed in that certain groups (e.g., Men, students, professionals, etc.) may be over- or under-represented.
What is a random sample? - AO1
- Every person in the target population has an equal chance of being selected
- Lottery method. All members of the target population are given a number + placed in a hat or computer/phone randomiser used
What is a strength and limitation of random sampling? - AO3
- S = potentially unbiased. Means that CVs/EVs are controlled, which enhances internal validity
- L = Time-consuming and may not work. A complete list of population is hard to get + some participants may refuse to take part
What is a systematic sample? - AO1
- Participants are selected using a set ‘pattern’ (sampling frame) e.g. list in alphabetical order
- Every nth person is selected from a list of the target population
What is a strength and limitation of systematic sampling? - AO3
- S = Unbiased. The first item is usually selected at random. Objective method
- L = Time and effort. A complete list of the population is required, so may as well use random sampling
What is a stratified sample? - AO1
- Strata; sample reflects proportions of people in certain subgroups (strata) within a population
- Subgroups are identified, e.g. gender or age groups. The relative percentages of the population are reflected in the sample
What is a strength and limitation of stratified sampling? - AO3
- S = Representative method. The characteristics of the target population are represented. Generalisability more likely than other methods
- L = stratification is not perfect. Strata cannot reflect all ways in which people are different. Complete representation is not possible
What is an opportunity sample? - AO1
- People who are simply most available, i.e. the ones who are nearest/easiest to obtain
- Ask people nearby, e.g. ask the students in your class to take part or ask people who walk past you in a shopping centre
What is a strength and limitation of opportunity sampling? - AO3
- S = Quick method. Opportunity sampling is convenient because you just make use of the people who are closest. This makes it cheaper + one of the most popular sampling methods
- L = Inevitably biassed. The sample is unrepresentative of the target population as it’s drawn from a very specific area, such as one street in one town. Means the findings cannot be generalised
What is a volunteer sample? - AO1
- In a volunteer sample, participants select themselves
- Advertise. For example, place an advert in a newspaper or ask people to put hands up to volunteer
What is a strength and limitation of volunteer sampling? - AO3
- S = Participants are willing. Participants have selected themselves + know how much time and effort is involved. Likely to engage more than people stopped in the street
- L = Volunteer vias. Participants share certain traits, e.g. want to be helpful. Respond to cues and generalisation limitedb
What are ethical issues? - AO1
- what are the 4 principles they’re based on
When a conflict exists between the rights of participants and the aims of the research.
- BPS Code of Conduct is a quasi-legal document to protect participants based on 4 principles: Respect, Competence, Responsibility and Integrity.
- Ethics Committee weighs up Costs (e.g. Potential harm) and benefits (e.g. Value of research) before deciding whether a study should go ahead.
Why is informed consent important? - AO1
- What is the issue
Issue: Informed judgement about whether to take part. But may reveal aims.
Sign consent form where appropriate. Seek parental consent. Alternative forms of consent are:
- Presumptive: Ask a similar group.
- Prior general: agreed to be deceived.
- Retrospective: Get consent after the study.
What is Deception? - AO1
- What is the issue
Issue: Misleading or withholding information so consent is not informed. But mild deception OK.
At the end of a study, participants should be given a debrief where they are advised of:
- The true aims of the investigation.
- Details that were not given during the study e.g. existence of other groups or conditions.
- What their data will be used for
- Their right to withhold data.
Why is protection from harm important? - AO1
- What is the issue
Issue: Participants should be at no more risk than they would be in everyday life.
- Should be given the right to withdraw at each stage of the research process.
- Should be reassured that their behaviour was typical/normal during the debriefing.
- You should provide counselling if participants have been e.g. distressed.
Why is privacy and confidentiality important? - AO1
- What is the issue
Issue: We have the right to control information about ourselves. If this is invaded, confidentiality should be respected.
- If personal details are held, these must be protected (a legal requirement). Usually no personal details are recorded.
- Researchers refer to participants using numbers, initials or false names.
- Participants’ personal data cannot be shared with other researchers.
What is a Correlation? - AO1
- Illustrates the strength and direction of an association between two Co-variables.
What is a Scattergram - AO1
- Co-variable is on the X axis, the other is on the Y axis.
What are the 3 types of correlation? - AO1
- Positive correlation - co-variables increase together.
- Negative correlation - one co-variable increases, the other decreases
- Zero correlation - no relationship between two variables
What is the difference between correlations and experiments? - AO1
- In an experiment, the researcher manipulates the IV and records the effect on the DV.
- In correlation, there is no manipulation of variables and so cause and effect cannot be demonstrated.
What is one strength of correlations? - AO3
Useful starting point for research.
- By assessing the strength and direction of a relationship, correlations provide a measure of how 2 variables are related.
- If variables are strongly related, it may suggest hypotheses for future research.
What is another strength of correlations? - AO3
Relatively economical.
- Unlike a lab study, there is no need for a controlled environment and can use secondary data. e.g., government statistics.
- So correlations are less time-consuming than experiments.
What is one limitation of correlations? - AO3
No cause and effect.
- Correlations are often presented as casual, e.g. by the media, when they only show how 2 variables are related.
- This leads to false conclusions about causes of behaviour.
What is another limitation of correlations? - AO3
Intervening variables.
- Another untested variable may explain the relationship between co-variables.
- They also lead to false conclusions.
What are observational techniques? - AO1
- A way of seeing or listening to what people do without having to ask them. Observation is often used within an experiment as a way of assessing the DV.
What is one strength of observational techniques? - AO3
Capture what people do.
- People often act differently from how they say they will in self-report methods.
- Observations are useful as they give insight into spontaneous behaviour.
What is one limitation of observational techniques? - AO3
Risk of observer bias.
- Researchers’ interpretation of the situation may be affected by expectations.
- Bias can be reduced using more than one observer.
What are the 3 different types of observation? - AO1
- Naturalistic and controlled observation.
- Covert and overt observation.
- Participant and non-participant observation.
What is naturalistic observation? - AO1
Takes place where the target behaviour would normally occur.
What is one strength of naturalistic observation? - AO3
High external validity.
- In a natural context, behaviour is likely to be more spontaneous.
- More generalisable to everyday life.
What is one limitation of naturalistic observation? - AO3
Low control.
- There may be uncontrolled CVs/EVs.
- Makes it more difficult to detect patterns.
What is a controlled observation? - AO1
Some control/manipulation of variables, including control of CVs/EVs.
What is one strength of controlled observation? - AO3
Can be replicated.
- More easily repeated due to standardised procedures.
- Findings can be checked to see if they occur again.
What is one limitation of controlled observation? - AO3
May have low external validity.
- Behaviour may be contrived as a result of the setting.
- Findings cannot be applied to everyday experience.
What is a covert observation? - AO1
Participants are unaware they are being studied.
What is one strength of a covert observation? - AO3
Demand characteristics are reduced.
- Participants do not know they are being watched, so their behaviour will be more natural.
- Increases the internal validity of the findings.
What is one limitation of a covert observation? - AO3
Ethically questionable.
- People may not want behaviour recorded even in public.
- Participants’ right to privacy may be affected.
What is an overt observation? - AO1
Are aware they are being studied.
What is one strength of an overt observation? - AO3
More ethically acceptable.
- Parents have given their consent to be studied.
- They have the right to withdraw if they wish.
What is one limitation of an overt observation? - AO3
Demand characteristics.
- Knowledge of being studied influences behaviour.
- Reduces the internal validity of the findings.
What is a participant observation? - AO1
Researcher becomes part of the group they’re studying.
What is one strength of a participant observation? - AO3
Can lead to greater insight.
- Researcher experiences the situation as the participants do.
- This enhances the external validity of the findings.
What is one limitation of a participant observation? - AO3
Possible loss of objectivity.
- The researcher may identify too strongly with those they’re studying.
- They reduce the external validity of the findings.
What is a non-participant observation? - AO1
Researcher remain separate from the group they’re studying.
What is one strength of a non-participant observation? - AO3
More objective.
- Researcher maintains an objective distance, so less chance of bias.
- May increase the internal validity of the findings.
What is one limitation of a non-participant observation? - AO3
Loss of insight.
- Researcher may be too far removed from those they are studying.
- May reduce the external validity of the findings.
What are the three observational designs?
- Behavioural categories
- Event sampling
- Time sampling
What are behavioural categories? - AO1
The target behaviour to be observed should be broken up into a set of observable categories.
- this is similar to operationalisation
What is one limitation of behavioural categories? - AO3
Difficult to make clear and unambiguous.
- Categories should be self-evident and not overlap. Not always possible to achieve.
- ‘Smiling’ and ‘grinning’ would be poor categories.
What is another limitation of behavioural categories? - AO3
Dustbin categories.
- All forms of behaviour should be in the list and not one ‘dustbin’.
- ‘Dumped’ behaviours go unrecorded.
What is event sampling? - AO1
A target behaviour/event is recorded every time it occurs.
What is one strength of event sampling? - AO3
Useful for infrequent behaviour.
- The researcher will still ‘pick up’ behaviours that do not occur at regular intervals.
- Such behaviours could easily be missed using time sampling.
What is one limitation of event sampling? - AO3
Complex behaviour oversimplified.
- If the event is too complex, important details may go unrecorded.
- This may affect the validity of the findings.
What is time sampling? - AO1
Observations are made at regular intervals, e.g. once every 15 seconds.
What is one strength of time sampling? - AO3
Reduces the number of observations.
- Rather than recording everything that is seen (i.e. continuous) data is recorded at certain intervals.
- The observation is more structured and systematic.
What is one limitation of time sampling? - AO3
May be unrepresentative.
- The researcher may miss important details outside of the timescale.
- May not reflect the whole behaviour.
What are the two different self-report techniques? - AO1
- Questionnaires
- Interviews (structured and unstructured)
What are questionnaires? - AO1
- what can they be used for
They are made up of a pre-set list of written questions (or items) to which a participant responds
- They can be used as part of an experiment to assess the DV
What is one strength of questionnaires?- AO3
Can be distributed to lots of people
- gather large amounts of data quickly and researcher need not to be present when completed
- reduces the effort involved and makes questionnaires cost-effective
What is another strength of questionnaires?- AO3
Straightforward to analyse
- especially if closed, fixed-choice questions are used
- statistical data can easily be converted to graphs and charts for comparison
What is one limitation of questionnaires?- AO3
Responses may not always be truthful
- respondents tend to present themselves in a positive light
- thus social desirability bias is possible
What is another limitation of questionnaires?- AO3
Response bias
- respondents may favour a particular kind of response, e.g. they always agree
- this means that all respondents tend to reply in a similar way
What is an interview? - AO1
face -to-face or online interaction between an interviewer and interviewee
What is a structured interview? - AO1
List of pre-determined questions asked in a fixed order
What is one strength of a structured interview?- AO3
Easy to replicate
- straightforward to replicate because of standardised format
- the format also reduces differences between interviewers
What is one limitation of a structured interview?- AO3
Interviewers cannot elaborate
- interviewers cannot deviate from the topic or explain their questions
- this may limit the richness of data collected
What is an unstructured interview? - AO1
No set questions, there is a general topic to be discussed but the interaction is free-flowing and the interviewee is encouraged to elaborate
What is one strength of an unstructured interview?- AO3
There is greater flexibility
- unlike a structured interview, points can be followed up as they arise
- more likely to gain insight into interviewee’s worldview and collect unexpected information
What is one limitation of an unstructured interview? - AO3
Increased risk of interviewer bias
- closer dialogue between interviewer and interviewee
- means more opportunity for unconscious cues
What is a semi-structured interview? - AO1
A list of questions that have been worked out in advance but interviewers ask further questions based on previous answers
What does questionnaire construction involve? - AO1
Designing questionnaires includes the use of open and closed questions
How do you write good interview questions? - AO1
- what are the three things to avoid; give examples
- avoid jargon: ‘do you agree that maternal deprivation in infanthood inevitably leads to affectionless psychopathy?’
- avoid double-barrelled questions: ‘do you agree that footballers are overpaid and should give 20% of their wages to charity?’
- avoid leading questions: ‘do you agree that boxing is barbaric?’
What is a closed question? - AO1
- what type of data do these questions tend to produce
Respondent has limited choices
- Data produced tends to be quantitative, e.g. ‘how many cigarettes do you smoke in a day? 0-10, 11-29, 21-30+’
- But can produce qualitative data, e.g. ‘do you smoke? yes/no, and then convert to quantitative’
What is the strength of closed questions? - AO3
Easy to analyse
- can produce graphs and charts for comparison
- makes it easier to draw conclusions
What is the limitation of closed questions? - AO3
Responses are restricted
- forced into an answer that may not represent true feelings
- may reduce the validity of the findings
What is an open question? - AO1
- what type of data do these questions tend to produce
Respondent provides own answers expressed in words
- Data produced tends to be qualitative, e.g. ‘why did you start smoking?’ This question would produce a range of personal answers
What is the strength of open questions? - AO3
Responses not restricted
- answer more likely to provide detailed, unexpected information
- likely to have more external validity than statistics
What is the limitation of open questions? - AO3
Difficult to analyse
- wider variety of answers than produced by closed questions
- may be forced to reduce data to statistics
What does interview construction involve? - AO1
An interview schedules, quiet room, rapport and ethics
How will an interview schedule help an interview? - AO1
A standardised list of questions that the interviewer needs to cover can reduce interviewer bias.
How will a quiet room help an interview? - AO1
Will increase the likelihood that the interviewee will open up
How will a rapport help an interview? - AO1
Begin with neutral questions to make participants feel relaxed
How will ethics help an interview? - AO1
Remind interviewees that answers will be treated in confidence
What is a pilot study? - AO1
A pilot study is a small-scale trial run of a research design (procedure, questionnaires, etc.) using a small number of participants.
- it is used in all types of research
What is the aim of piloting? - AO1
To find out if certain things don’t work so you can correct them before spending time and money on the real thing
What are the different types of data? - AO1
- qualitative data and quantitative data
- primary and secondary data, including meta-analysis
What is qualitative data? - AO1
Non numerical data expressed in words, e.g. an extract from a diary.
What is the strength of qualitative data? - AO3
Richness of detail.
- Much broader in scope than quantitative data.
- More meaningful, greater external validity.
What is the limitation of qualitative data? - AO3
Difficult to analyse.
- Hard to identify patterns and make comparisons.
- Leads to subjective interpretation and researcher bias.
What is Quantitative data? - AO1
Numerical data e.g. Reaction time or number of mistakes.
What is the strength of quantitative data? - AO3
Easier to analyse.
- Can draw graphs and calculate averages.
- So comparisons between groups can be made.
What is the limitation of quantitative data? - AO3
Narrower in meaning.
- Expresses less detail than qualitative data.
- Lower external validity - may be less like ‘real life’.
What is primary data? - AO1
‘First-hand’ data collected for the purpose of the investigation.
What is the strength of primary data? - AO3
Fits the job.
- study designed to extract only the data needed.
- Information is directly relevant to research aims.
What is the limitation of primary data? - AO3
Requires time and effort.
- Designing and collating and questionnaires takes time and expense.
- Secondary data can be assessed within minutes.
What is secondary data? - AO1
Collected by someone other than the person who is conducting the research.
What is the strength of secondary data? - AO3
Inexpensive.
- The desired information may already exist.
- Requires minimal effort making it inexpensive.
What is the limitation of secondary data? - AO3
Quality may be poor.
- Information may be outdated or incomplete.
- Challenges the validity of any conclusions.
What is meta-analysis? - AO1
A type of secondary data that involves combining data from a large number of studies. Calculation of effect size.
What is the strength of meta-analysis? - AO3
Increases validity of conclusions.
- The eventual sample size is much larger than individual samples.
- Increases the extent to which generalisations can be made.
What is the limitation of meta-analysis? - AO3
Publication bias
- Researchers may not select all relevant studies, leaving out negative or non significant results.
- Therefore, conclusions may lack validity.
What are the three measures of central tendency? - AO1
- Mean.
- Median.
- mode
What is a mean? - AO1
Arithmetic average. Add up all the scores and divide by the number of scores.
What is the strength of a mean? - AO3
Sensitive measure.
- Includes all the scores/values in the data set within the calculation.
- Represents data set better than median or mode.
What is the limitation of a mean? - AO3
May be unrepresentative.
- One very large or small number makes it distorted.
- The median or the mode tend not to be so easily distorted.
What is a median? - AO1
Middle value places scores in ascending order and select middle value. If there are two values in the middle, the mean of these is calculated.
What is the strength of a median? - AO3
Less affected by extreme scores.
- The median is only focused on the middle value.
- In some cases it may be more representative of the data set as a whole.
What is the limitation of a median? - AO3
Less sensitive than the mean.
- Actual values of lower and higher numbers are ignored.
- Extreme values may be important.
What is a mode? - AO1
Most frequent or common value used with categorical/nominal data.
What is the strength of a mode? - AO3
Relevant to categorical data.
- When data is discrete, i.e. represented in categories.
- Times the mode is the only appropriate measure.
What is the limitation of a mode? - AO3
An overly simple measure.
- The mode may be at one extreme.
- It is not a useful way of describing data when there are many modes.
What are the two measures of dispersion? - AO1
- range
- standard deviation
What is a range? - AO1
The difference between highest to lowest value. (Sometimes one is added if values had been rounded up or down)
What is the strength of a range? - AO3
Easy to calculate.
- Values in order and subtract largest from the smallest.
- Simple formula, easier than the standard deviation.
What is the limitation of a range? - AO3
Does not account for the distribution of the scores.
- The range does not indicate whether most numbers are closely grouped around the mean or spread out evenly.
- The standard deviation is a much better measure of dispersion in this respect.
What is standard deviation? - AO1
Measure of the average spread around the mean. The larger the standard deviation, the more spread out the data is.
What is the strength of standard deviation? - AO3
More precise than the range.
- Includes all values within the calculation.
- Therefore, more accurate picture of the overall distribution of data set.
What is the limitation of standard deviation? - AO3
May be misleading.
- Can be distorted by extreme values.
- Also, extreme values may not be revealed, unlike with the range.
What are the 4 presentations of quantitative data? - AO1
- tables
- bar charts
- histograms
- scattergrams
What are tables? - AO1
- Raw scores displayed in columns and rows
- a summary paragraph beneath the table explains the findings and draws conclusions
What are bar charts? - AO1
- categories (discrete data) are usually placed along the x-axis and frequency on the y-axis (or can be reversed)
- the height of each column represents the frequency of that item
What are histograms? - AO1
bars touch each other (in bar charts they don’t) - data is continuous rather than discrete. There is a true zero
What are scattergrams? - AO1
- used for correlational analysis. Each dot represents one pair of related data. Illustrates strength and direction of correlation
- the data on both axes must be continuous
What are the 2 types of distribution? - AO1
- normal distribution
- skewed distribution (negatively skewed and positively skewed)
What is normal distribution? - AO1
- symmetrical, bell-shaped curve. Most items are in the middle area of the curve with very few at the extreme ends
- the mean, median and mode all occupy the same mid-point of the curve
What is skewed distribution? - AO1
distributions that lean to one side or the other because most items are either at the lower or upper end of the distribution
What is a negative skew? - AO1
- most of the distribution is concentrated towards the right of the graph, resulting in a long tail on the left
- the mode is the highest point of the peak, median comes next then mean is dragged across to the left (if scores are arranged from lowest to highest)
What is a negative skew? - AO1
- most of the distribution is concentrated towards the left of the graph, resulting in a long tail on the right
- the mode is the highest point of the peak, median comes next then the mean is dragged across to the right (if scores are arranged from lowest to highest))
Explain estimates and order of magnitude calculations. - AO1
Estimates - give a number to just 1 or 2 significant figures
Order of magnitude - calculate standard form and compare exponents
What is the significance of statistical testing? - AO1
- what is it
The difference/association between 2 sets of data is greater than what would occur by chance, i.e. it is a meaningful result
- to find out if the difference/association us significant we need to use a statistical test
What is probability? - AO1
- what is it
Probability (p) is about likelihood.
- The accepted level of probability in psychology is 0.05, a significance level of 5%. This is the level at which a researcher decides to accept or reject the null hypothesis.
- Even though psychologists may find statistically significant differences/ relationships within data, they can never find statistical certainties. This is why psychologists use phrases such as ‘this suggests’, rather than ‘this proves’.
What are calculated and critical values? - AO1
- how are they produced
- The researcher uses a statistical test to produce a calculated value.
- The calculated value is compared with a critical value to decide whether the result is significant or not.
- The critical values for a particular test are given in a table of critical values.
How do you find the critical value? - AO1
To find the critical value, need to know:
1. The significance level (usually 0.05 or 5%).
2. The number of participants in the investigation (the N value) or the degrees of freedom (df).
3. Their hypothesis is directional (one-tailed test) or non directional (two-tailed test).
What are the conditions of use in the sign test? - AO1
- Used to analyse the difference in scores between related items e.g. The same participant is tested twice (Repeated measures).
- Can be used with nominal data (or better)
What is the calculation used in the sign test? - AO1
- The score for condition B is subtracted from the condition A should produce the sign of difference (either a + or a -).
- Add up the numbers of pluses and the numbers of minuses.
- Participants who achieved the same score in condition A and condition B should be disregarded and deducted from the N value.
- The S value is the total of the less frequent sign.
What is the significance of the critical value in the sign test? - AO1
If S is equal to or less than the critical value, then S is significant and the null hypothesis is rejected and the alternative hypothesis accepted at the 5% level of certainty.
What is peer review? - AO1
- Before publication, all aspects of the investigation are scrutinised by experts, ‘peers’, in the field.
- These experts should be objective and unknown to the researcher.
What are the aims of peer review? - AO1
- Funding: Allocate research funding.
- Validation of the quality and relevance of research.
- Improvements and amendments are suggested.
What is the strength of peer review? - AO3
Protects quality of published research.
- Minimises possibility of fraudulent research, and means published research is of the highest quality.
- Serves the reputation of psychology as a science and increases the credibility and status of the subject.
What is a limitation of peer review? - AO3
Anonymity may be used to criticise rival research.
- A minority of reviewers may use their anonymous status to criticise rival researchers.
- Often there is competition for limited research funding, so this may be an issue.
What is another limitation of peer review? - AO3
Publication bias.
- Tendency for editors of journals to want to publish ‘headline-grabbing’ findings.
- That research that does not meet this criterion is ignored.
What is a third limitation of peer review? - AO3
Ground-breaking research may be buried.
- Reviewers may be much more critical of research that contradicts their own view
- Pair review may slow down the rate of change within scientific disciplines.
What can psychological research benefit? - AO1
The findings of psychological research can benefit our financial prosperity
What are the 2 implications of psychological research for the economy? - AO1
- Attachment research into the role of the father
- The development of treatment for mental disorder
How does attachment research into the role of the father help the economy? - AO1
- Recent research has stressed the importance of the father in a child’s healthy psychological development.
- This may promote more flexible working arrangements in the family.
- This means that modern parents are better equipped to contribute more effectively to the economy.
How does the development of treatment for mental disorder help the economy? - AO1
- A third of all days off work are caused by mental disorders such as depression.
- Psychological research into the causes and treatments of mental disorders means that people have access to therapies or psychotherapeutic drugs such as SSRIs
- People with mental disorders can manage their condition effectively, return to work and contribute to the economy.
What is correlation? - AO1
A mathematical technique in which a researcher investigates an association between two variables, called co-variables
What is a correlation coefficient? - AO1
A number between -1 and +1 that represents the direction and strength of a relationship between co-variable
