Research methods
- Created by: em.c
- Created on: 03-05-15 18:34
Definitions
Extraneous variables = external variables that are unwanted and could affect whats being measured
Confounding variables = when the extraneous variables have an effect and mask true result
Aims = general statement of why study is being carried out
Hypothesis = a clear statement, prediction, testable, can be directional/non-directional
External validity = the extent to which you can apply results to other people/places/situations
Inter-rater reliability = extent to which two or more people agree when analyzing behaviour
Internal validity = are we measuring what we intend to within the study
Event sampling = focuses only on actions/events that of particular interest to researcher
Time sampling = observations made only during specified time periods
Point sampling = individual is observed in order to categorise current behvaiour after which a second is observed and so on
Experiment Methods
Lab exp - +ves: -ves
- Can be replicated Lacks external validity
- Less risk of extraneous variables Demand characteristics
- Good control of variables Lacks mundane realism
- Establishes C/E
Field Experiment - natural but IV still manipulated
- No evaluation apprehension Lots of extraneous variables
- High external validity Low in internal validity
- Can establish relationships Ethical issue - informed consent
Natural Experiment - pre-existing groups, type of Quasi experiment
- Pps not aware No random allocation
- High ecological validity IV not directly manipulated
- Look things unethical to manipulate Difficult to identify what causes behaviour
Experiment Methods cont.
Case Studies:
- Produces rich detailed data Results cannot be generalised
- Permits study over time No control over extraneous variables
- Study a topic unethical to manipulate Researcher bias may be a problems
Interviews
- Good reliability Hard to analyse
- Non-verbal cues Social desirability bias
- Lots of personal information Only get info person consciously aware of
Questionnaires
- Easy to analyse (numerical data) Social desirability bias
- Large amounts of data short amount of time Many poorly constructed
- Reasonable validity and highly reliable Often used in correlational studies - noC/E
Quasi Exp: Looks like an exp, features are weak, can't randomly allocate pps to conditions
Interviews
Non-directive interview: Interviewee free to discuss, Interviewer guides, useful in treatment of mental disorders, less relevant to research
Semi-structured: Interviewer knows topics and order, interviewees same qus in same order
Clinical: same questions, but some can be added, flexible, questions asked depend on answers
Fully structured: Set questions,order and answers yes/no/don't know
Xs Interviewer bias
Single blind procedure - interviewer knows hypothesis, interviewee doesnt reduces demand characteristics
Double blind procedure - eliminates investigator effects as someone other than researcher asks questions
Questionnaires
- Open (qualitative) and closed (quantitative)
- Open strength: in depth detailed info, weakness: difficult to analyse
- Closed strength: easy to analyse, weakness:don't provide much information
- Can be too complex and ambiguous
- Psychologists should avoid leading qus and double barrelled items
- Test-retest technique - no of individuals given same questionnaire on different occasions and scores correlated High correlation = reliable
- Validity - comparing scores on a questionnaire to external criteria
- Standardisation: tests administered to large sample so results can be compared to others
- Split-half technique - set of questionnaires, split in two scores from one half compared with the other half
Observations
Natural Observations:
- Pps behave naturally No control over variables - hard to establish C/E
- Provide richer and fuller info Training observers difficult and expensive
- Easier to generalise to real life Impossible to replicate
Controlled Observations
- Less risk of extraneous variables Artificial situation people won't behave naturally
- Can establish c/e Little external validity
- More complete data than experiments as Investigator effects witnessing some natural behvaiour Demand characteristics
Hypotheses and Content analysis
Experimental (or alternative) hypothesis - prediction for an experiment when IV changes
Null hypothesis - Predicts no change and is easier to disprove than prove
Directional hypothesis - one tailed hypothesis - says which direction the change will be
Non-directional hypothesis - two tailed - doesn't state the way the change will go
Content analysis - analysis of behaviours, written or spoken word into pre-set categories, known as coding. Can make qualitive data quantitative
- + - Gives opportunity to understand people as rounded indviduals in a social context
- + - Can reduce complex behaviours/info into manageable categories
- + - Suggest interesting hypotheses that could be tested in subsequent research
- - - Social desirability bias
- - - Data may be very unrepresentative making it hard to generalise
- - - Researcher collects a huge amount of material then they could show bias by emphasising only the info that favours their hypothesis
Research design
Independent groups - different pps experience each condition - only experience one condition
- Identical stimulus materials Greater extraneous variables
- Demand characteristics less likely More pps -> more expensive
- Absence of order effects
Repeated measures - same pp experiences each condition - experience both conditions
- Reduced extraneous variables Order effects - can counterbalance
- Fewer pps needed - cheaper Demand characteristics more likely May need different stimulus materials
Matched pairs - different pps closely matched experience each condition - each half 1 condition
- Absence of order effects Difficult to find well-matched pairs
- Identical stimulus materials
- Demand characterisitcs less likely
Counterbalance - one group do AB, other BA
Order effects - constant errors introduced to an experiment because of repetition
Sampling techniques
Random sample
- Every member of population equal chance of being chosen - most representative
- May not all be available to do study, may opt out of study
Volunteer sample
- Pps volunteer when asked or in response to an advert
- May be a volunteer bias - demand characteristics
Opportunity sample
- Most common involves people who are there at the time and fit criteria you are looking for
- Unrepresentative (might be), quite narrow
Stratified sample
- Classifiying into categories then choosing a sample which consists of pps from each category in the same proportions as they are in population
BPS code of Ethics
- Psychological consequences
- Get informed consent
- Avoid deception
- Pps should be able to withdraw at any point
- Pps should be debriefed after the study
- Pps have the right to expect confidentiality
- Pps should be protected from harm
- Psychologists should not encroach on pps privacy
- Psychologists should only give advice on matters for which they are qualified
- Colleagues research
Data Analysis
- Nominal data - used when categorising something into named groups
- Ranked/ordinal data - data ranked so possible see order of scores in relation to each other
- Interval/ratio data - gives rank order of scores and precise intervals between scores
Measures of central tendency -mean,median,mode
Mean
- More sensitive than median Misrepresentative with outlier
- Uses all data
Median
- Not affected by extremes Less sensitive than mean
Mode
- Useful when data in categories Not useful when several modes
Data Analysis 2
Measures of dispersion - range and standard deviation
Range - difference between highest and lowest scores
Standard Deviation: Average amount all scores deviate from mean
To calculate standard deviation:
- Difference between each score and mean of those scores is calculated + then squared
- Squared deviaitons are added and their mean calculated to give value known as variance
- Square root of the variance gives standard deviation of the scores
Graphs -histograms (interval data only),bar charts, pie charts, freq. polygrams, scattergraphs
Correlational studies are used to asses strength of relationship between variables, no direct manipulation of IV by experimenter
Correlation coefficients - way of measuring strength of relationship +1 perfect positive, 0 no correlation, -1 perfect negative
Data Analysis 3
Correlations:
- Quick and easy to collect data Can't establish C/E
- Easy to establish trends between variables Problem of extraneous variables
- Can do correlations where exps. unethical Ethical issues - studies sensitive
Quantitative:
- Objective No details
- Scientific Hard to fit into categories
- Patterns No feelings/emotions
Qualitative:
- Chronological order Subjective - opinions
- Degrees of severity Can be exaggerations
- More detailed
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