Psychological Investigations Flashcards
What is quantitative data?
Data that is numerical
What is qualitative data?
Data that is non-numerical
What is validity?
Whether or not an investigation measures what it claims to measure.
What is the DV?
The dependent variable, the thing that is being measured in an experiment.
What is the IV?
The Independent variable, the thing that is being manipulated or changed.
What is a null hypothesis?
The mathematical acknowledgement that the results are due to chance. It will begin with ‘there is no difference/correlation between….
What is an experimental hypothesis?
A statement that can be tested
What is an experiment?
A study of cause and effect.
What is the independent variable?
The variable that has been manipulated.
What is the dependent variable?
The variable that is measured.
What is the control variable?
A variable that is not changed and allows for a fair test.\
What is an extraneous variable?
A variable that could effect the outcome which we cannot control.
What is a confounding variable?
If we cannot control a variable and it DOES seriously affect the outcome, then it is confounding.
What is a field experiment?
an experiment conducted in a natural environment. The variables are still manipulated, but participants may be in their their natural environment and may not know that they are in an experiment.
What are the strengths of a natural experiment?
- high ecological validity (as more like and can be generalised to real life)
- less demand characteristics (subjects may not know they are in experiment)
- less bias sampling (subjects do not need to be taken to a lab)
What are the weaknesses of a field experiment?
- extraneous variables cause bias (difficult to control)
- more difficult to replicate
- ethical issues of consent, deception, etc. are likely to occur
What are the weaknesses of a field experiment?
- Less valid due to extraneous variables
- Difficult to replicate exactly
- Ethical issues (consent, deception, invasion of privacy)
What is a laboratory experiment?
An experiment in a special environment, participants are likely to know that they are in an experiment, but they may not know the true aims.
what are the strengths of a lab experiment?
- Manipulation of variables mean strong inference of case an effect
- Increased control and measuring variables is more accurate
- It is easy to replicate
What are the weaknesses of a laboratory experiment?
- Still can’t control ALL of the variables
- Low ecological validity (not natural environment so cannot be generalised to real life)
- Results may be bias due to sampling
- Demand characteristics may be high
- Ethical problems of deception
What is a natural experiment?
A quasi experiment. The IV is changed by a natural occurrence, and the effects of the DV are just recorded. Nothing is manipulated by the researcher.
What are the strengths of a quasi experiment?
VERY good ecological validity - natural change
Very little bias from sampling and demand characteristics
What are the weaknesses of a natural experiment?
- Difficult to infer cause and effect
- Virtually impossible to replicate
- Bias if participants know they are in a study
- Ethical issues
What is repeated measures design?
when the experimenter uses the same group of participants in both conditions of the experiment.
What are the strengths of the repeated measures design?
- Subject variables are constant so will not be extraneous
- Better stats tests as less variation between conditions
- Less subjects, more economical
What are the weaknesses of repeated measures design?
- Order effects (fatigue, practice, boredom) may be issues
- Demand characteristics/ social desirability if aim is guessed
- Different tests to test the same thing may be needed
What is the independent measures design?
Uses completely different subjects in each conditio.
What are the strengths of independent measures design?
- Order effects are no problem
- Demand characteristics are not problematic (harder to guess the aim)
- Sane test can be used both times
What are the weaknesses of using independent measures?
- Subject variables differ (could be confounding)
- Worse statistical tests (less consistency between conditions)
- More subjects needed (less economical)
What is the matched pairs design?
different participants are used in each condition, but in each condition they are matched on a specific aspect.
What are the advantages of matched pairs design?
- Consistent (ish) subject variables
- Better statistical tests (less varied between conditions)
- Demand characteristics not much problem
- Same test can be used
What are the weaknesses of matched pairs design?
- Subject variables can not be perfectly matched
- Matching is time consuming
- More subjects are eeded
