Research Methods - Need to do booklet 3 Flashcards
What are the key features of an experiment?
- Investigates the difference between two conditions
- Manipulation and measurement of variables
- To test a hypothesis
- To establish ‘cause and effect’
What is a purpose of an aim?
- To identify what variables the study is investigating
- To explain the outline and purpose of the study
What is the independent variable?
What the researcher manipulates in the experiment
What is the dependant variable?
What the researchers measures in the experiment
What is an experimental hypothesis?
A prediction about the expected outcome of an experiment. It is wrote as a precise and testable statement.
What is a null hypothesis?
- This is the hypothesis the researcher is trying to disprove
- It states that the results will not be significant in terms of supporting the idea being investigated
What is operationalisation?
Describing the variables in terms of how they will be precisely manipulated and measured
What are the two experimental hypothesis?
- Directional
- Non directional
What is a directional hypothesis also known as?
One tailed
What is a directional hypothesis?
The hypothesis specifically states the direction of the results
When is a directional hypothesis usually used?
When previous/past research has shown a particular outcome is likely
What is a non directional hypothesis also known as?
Two tailed
What is a non directional hypothesis?
The hypothesis does not specify the expected directional of the results
When is a non directional hypothesis used?
When there is little or previous research
What are the key features of Laboratory experiments?
- Controlled in a tightly, controlled, artificial environment
- Experimenter deliberately manipulates the independent variables
-Experimenter measures the dependant - Attempt to control/minimise other variables that could effect dv
- Standardised procedure
What are the key features of field experiments?
- Conducted in a natural, real world environment
- Experimenter deliberately manipulates the IV
- Experimenter measures DV
- There is minimal control of other variables that can affect DV
What are the key features of natural experiments?
- Can be conducted in any setting
- IV is naturally occurring
- The IV is an event/experience
- Experimenter measures DV
- Little/no control of other variables
What are the key features of Quasi experiments?
- Can be conducted in any setting
- IV is naturally occuring
- IV is a pre-existing characteristic (age, gender etc)
- Experimenter measures the DV
- Has little or no control over other variables that could affect DV
What does standardisation mean?
Procedures and conditions being controlled and kept the same across all conditions allowing for replication
What does ecological validity mean?
The extent to which the experimental setting represents real life situations and behaviour
What does demand characteristics mean?
Behaviour from participants in the experimental setting which may be unnatural and affect how they perform on tasks
What does validity mean?
The extent to which an experiment is accurate in measuring what it claims to measure
What does mundane realism mean?
The extent to which the tasks used in the experiment are representative of tasks completed in everyday life.
What does reliability mean?
The extent to which an experiment can be repeated to check the consistency of the results
What does internal validity mean?
The extent to which there is confidence in the IV causing an effect on the DV
What are the advantages of lab experiments?
- High internal validity (EVs controlled)
- High reliability (standardised procedure)
What are the disadvantages of lab experiment
- Low ecological validity and mundane realism (artificial tasks)
- High demand characteristics (P’s aware taking part in experiment)
What are the strengths of field experiments?
- High ecological validity and mundane realism (real life tasks)
- Low demand characteristics (P’s usually unaware they are taking part)
What are the weaknesses of field experiments?
- Low internal validity (Hard to control EVs)
- Low reliability (hard to standardise)
What are the advantages of natural and quasi experiments?
- Can study sensitive research questions (allows investigation of variables that would be harmful to manipulate)
- High mundane realism and ecological validity (everyday tasks)
What are the disadvantages of natural and quasi experiments?
- Low internal validity (IV not manipulated directly)
- Low reliability (naturally occurring IV and hard to standardised)
What is an extraneous variable?
A variable, other than the IV, that may affect the DV if it is not controlled
What is a confounding variable?
- A type of extraneous variable
- It is one that systematically changes alongside the IV
- Means It is possible it has caused a change to the DV
What is situational variables?
Features of the environment/ setting that might affect participants behaviour
How can you control situational variables?
Standardisation of all procedures
What are participant variables?
Individual differences between participants and the ways in which each participant varies from the other
How can you control participant variables?
Randomisation of participants to conditions
How can demand characteristics be controlled?
- Using some deception: not revealing true aim of study
- Double blind procedures: neither participant or researcher are aware of which conditions they’ve been assigned too
What is an investigator effect?
Any (unintentional or unconscious) unwanted influence of the researcher’s behaviour/characteristics on the participant’s data/outcome
How can investigator effect be controlled?
- Using the same researcher for all participants
- Double blind procedures
What does experimental designs mean?
How researchers are going to allocate and organise participants into conditions of an experiment
What are the three experimental designs?
- Repeated measures
- Independent groups
- Matched pairs
What is a repeated measures design?
Each participant does both conditions of an IV
What are the strengths of repeated measures design?
- Participant variables are controlled for
What are the disadvantages of repeated measures design?
- Demand characteristics likely to be experienced (become aware of what’s being manipulated)
- Order effects likely to be experienced
How can order effects be prevented in repeated measures design?
Counterbalancing, some do condition A and then B and vice versa
AB - BA
What is independent groups design?
Each participant does one condition of the IV - split equally
What are the advantages of independent groups design?
- Less chance of demand characteristics (only do one condition)
- Less chance of order effects (Only do one condition)
What are the disadvantages of independent groups design?
- Participant variables not controlled for
What is matched pairs design?
- Each participant is put into pairs by being matched on important variables (IQ, gender, age etc
- Each pair is split up into a condition (one in condition A and the other in condition B)
What is an advantage of matched pairs design?
- Less chance of demand characteristics and order effects
What is a disadvantage of matched pairs design?
Difficult to achieve
What does probability mean?
Refers to how sure that our results from an investigation are really significant and have not occurred by chance
What does a big probability mean in psychology?
- Bad
- More likely that the results have occurred by chance
What does a small probability mean in psychology?
- Good
- We can be confident that the results were not due to chance and are significant
How does psychologists calculate the probability of results being due to chance?
Statistical tests
What are the 8 statistical tests?
- Unrelated T-test
- Chi square
- Mann Whitney
- Related T-test
- Sign test
- Spearman’s Rho
- Pearsons r
- Wilcoxon
What probability do we use in psychology?
P is less than or equal to 0.05
What does P is less than or equal to 0.05 mean?
95% sure that the results are significant
What is the stringent level?
P is less than or equal to 0.01
When is stringent levels used?
If we need to be more confident than accepting a 5% probability the results are due to chance
What is the non-stringent level?
P is less than or equal to 0.1
When is non-stringent level used?
If we only need to demonstrate an effect/difference/relationship
What is a type 1 error also known as?
False positive
What is a type 1 error
Wrongly accepting the experimental hypothesis when the null should be accepted
When does a type 1 error occur?
With a non-stringent level
What is a type 2 error also known as?
False negative
What is a type 2 error?
Wrongly accepting the null hypothesis when the experimental hypothesis should be accepted
When does a type 2 error occur?
With the stringent level
How do you remember statistical tests?
- NOI (left down)
- RIC (Top row)
- Simon Cowell Wants More Singers Receiving Unanimous Praise (centre left to right)
What is the calculated/observed value in statistical tests?
The number produced after the statistical test has been calculated
What is the critical value table in statistical tests?
A value taken from a statistical test table which must be reached in order for results to be significant
How do you calculate a sign test?
- Calculate the difference between each participants two scores and note wether difference + or -
- Add up number of times + and - occurs
- The sign (+ or - ) that occurs less frequently is the calculated value and is known as ‘s’
- Calculate number of participants
- Interpret the significance.
When is a sign test significant?
The calculated value of S must be less than or equal to the critical value to be significant
When is a wilcoxon test significant?
The calculated value of T must be equal too or less than the critical value to be significant
When is a Mann Whitney test significant?
The calculated value of U must be equal to or less than the critical value to be significant
How do you calculate the df in a chi square experiment?
(number of rows - 1) x (number of columns - 1)
When is a chi-squared test significant?
The calculated value of chi must be greater than or equal to the critical value to be significant
When is a spearmans rho test significant?
The calculated value of rho must be equal too or more than the critical value to be significant
When is a Pearsons R test significant?
The calculated value of r must be equal too or more than the critical value to be significant
When is a unrelated T-test significant?
The calculated value of t must be equal to or more than the critical value to be significant
When is a related T-test significant?
The calculated value of t must be equal to or more than the critical value to be significant
How do you calculate the df in a related T-test?
N - 1
How do you calculate the df in a unrelated T-test
Na + Nb - 2
What is a target population?
The group of people who the researchers want to generalise (apply) their results too
What is a sample?
A small number of people taken from the target population who participated in the investigation
What is sampling bias?
When the sample selected under or over represent certain groups that compose the target population
What is random sampling?
- Where every participant in the target population has an equal chance of being selected through a lottery system,
- No bias from the psychologist
- Those selected are then contacted and invited to participant
What is an advantage of random sampling?
- Likely to be representative of the target population
What is an disadvantage of random sampling?
- Time consuming and inconvenient
What is opportunity sampling?
Approaching and inviting those who are available
What is an advantage of opportunity sampling?
More convenient to use
What is a disadvantage of opportunity sampling?
Unlikely to be representative of target population?
What is volunteer sampling?
- The sample is self selected
- Involves adverting the study and providing contact details so that individuals respond if they wish to participate in the study
What are the advantages of volunteer sampling?
More convenient
What are the disadvantages of volunteer sampling?
Unlikely to be representative of target population
What is systematic sampling?
- Involves devising a sampling frame and a system being nominated to select every Nth person.
- Those selected will be contacted and invited to participate
What is an advantage of systematic sampling?
Representative of target population
What is a disadvantage of systematic sampling?
Still possible to be unrepresentative of target population
What is stratified sampling?
- Identifying groups call strata that exist in the target population
- Calculating the proportions of individuals needed from each strata to represent the overall target population
What is an advantage of stratified sampling?
Very representative of target population
What is a disadvantage of stratified sampling?
Very time-consuming and inconvenient to use