PEACH PACK 1 - Hypotheses, Variables and Sampling Flashcards
FMGI
The scientific method
Way of gaining knowledge by forming theories, making predictions, gathering data and interpreting results
How does research begin? What needs to happen for research to be conside
Steps in the scientific method
- A phenomenon/behaviour is noticed
- Theories are developed to explain/describe this
- Hypotheses are written
- Studies are designed to test these predictions/answer these questions
- Data collection takes place
- Analysis of data collected
What do we measure in a correlational study?
How strongly two variables are ASSOCIATED. Correlations describe the relationship between two variables
They are both measured and neither one is set or controlled.
Positive… strong…
What do we establish in a correlational study?
The strength (strong or weak) and direction (positive or negative) of the association between these 2 variables.
What does a correlational hypothesis predict?
A constant association between 2 co-variables.
Alternate directional correlational hypothesis sentence
There will be a significant negative correlation between V1 and V2
NOT cause and effect relationship
Alternate non-directional correlational hypothesis statement
There will be a significant correlation between V1 and V2
IV + DV
What happens in a traditional scientific experiment?
The researcher is attempting to measure the effect of IV on DV by controlling all other variables. Allows researchers to establish cause-and-effect-links between 2 variables
IV
Variable which is manipulated by the experimenter
DV
Outcome which is measured by experimenter.
Results DEPEND on IV
What is an alternate hypothesis?
A prediction in the form of a testable statement
What do alternate hypothesis’ predict?
The direction of the outcome
Predicts…
Directional hypothesis
One-tailed
Predicts what direction the difference/correlation will be
There will be…
Experimental, alternate directional hypothesis statement
(IV 1st condition) will get better/worse scores (in the DV) than (IV 2nd condition)
Predicts…
Non-directional hypothesis
Two-tailed
Predicts only that there will be a difference/correlation, allowing for an outcome in either direction.
“There will be a significant difference/correlation”
There will be…
Experimental, alternate non-directional hypothesis statement
There will be a significant difference (in the DV) between (IV 1st condition) and (IV 2nd condition)
Predicts…
Null hypothesis
Non-directional, two-tailed
Predicts that the result the researcher gets are due to chance
There will be…
Experimental null hypothesis statement
There will be no significant difference (in the DV) between (IV1) and (IV2)
Validity
Extent to which a study has measured what it claims to measure
Operational definition of a variable
Said in precise terms how we will measure/manipulate it
In a hypothesis…
No need to answer Q
- We need to define how we will manipulate the IV
- Define how we will measure the DV
Extraneous variables
Variables that may have an effect on the DV apart from the IV
Confounding variables
Uncontrolled extraneous variables that have had an effect on results
Reliability
Extent to which a research finding is produced consistently over a number of investigations
Consistency
Situational variables
Variables in the research situation itself that can have an effect on the DV
Pilot studies
Smaller version of actual study allowing identification of problems
Participant variables
Variables coming from individual participants
What method is used to control participant variables?
Randomisation - random allocation of participants
What does randomisation allow us to assume?
That the differences between individual participants are balanced out
Order effects
When the same group of participants are required to carry out a task twice
What effect does ‘order effects’ have on performance?
Performance may improve or deteriorate due to practice or fatigue
What is used to control order effects, how and why?
Counterbalancing
Half the participants complete the task in one order, the other half in the opposite order.
Effects are balanced out
Demand characteristics
All of the cues that participants might receive that indicate the purpose of the research
Why are demand characteristics a problem and how are they controlled?
Participants may unconciously change behaviour as a result of these cues.
Low levels of deception is used to ‘throw participants off’ to disguise the true purpose of the questionnaire.
Researcher effects and an example
If a researcher knows the aims of the study and the expected outcome and struggle to remain objective and influence the results to reflect their expectation. Eg. mis-recording results/influencing participant behaviour/failing to follow standardised procedures
How can researcher effects be controlled?
Following standardised procedures.
IV + DV
What does an experimental hypothesis predict?
A cause-and-effect relationship between the IV and DV.
Predicting that manipulating the IV will cause a change/difference in the DV/
What is a representative sample?
A group of participants drawn from the target population that is typical of that target population
Why is a representative sample important?
Allows us to generalise from our results to the rest of the target population
What is sampling-bias?
Over-representation of one group of people
No longer appropriate to generalise
Random sample
A sample in which every member of the target population has an equal chance of being selected
One method of random sampling
The lottery method
What is the main advantage of random sampling?
Provides the best chance of an unbiased representative sample - everyone has opportunity to be chosen
One disadvantage of random sampling
Easy to end up with biased sample by chance
Name at least 2 non-random sampling techniques:
- Opportunity samples
- Volunteer samples
- Stratified sampling
What it is, advantages and disadvantages
Describe opportunity sampling
- Researcher selects participants who are available.
- Quick, convenient and efficient + ethical
- Tends to be unrepresentative as it is biased
- Participants are those who are willing to take part - specific characteristic
What it is, advantages and disadvantages
Describe volunteer sampling
- Self-selected samples where the participants have conciously decided to become involved in research
- Ethical as them volunteering is giving consent
- Allows access to a wide variety of participants
- Easy + convenient
- Biased as not everyone in the target population may see advert etc + participants are people who are most likely outgoing and helpful
What it is, advantages and disadvantages
Describe stratified sampling
- Dividing the target population into important strata/sub-categories which allow researcher to make sure certain groups are represented in sample.
- Because a deliberate effort is made to identify + select most important characteristics, sample will be fairly representative
- Identification of sub-categories by researcher may be biased - important sub-categories may be excluded from sample making it less representative
