How to do psychological research
- Created by: Philosophy Emma
- Created on: 10-10-19 11:29
Null hypothesis, H0
Hypothesises that there will be a negative effect of the independent variable
Example: alcohol does not increase reaction times
Alternative / experiemental hypothesis, H1
Hypothesises that there will be a positive result of the independent variable
Example: Alcohol increases reaction time
Falsifiable
There must be a reasonable way of showing that the hypothesis is wrong, this makes them falsifiable
Example: All swans are white
Is falsifiable because it can be disproven by finding a swan of a different colour
Directional / one-tailed hypothesis
Specifies the direction of the results
Examples: Alcohol increases reaction times
Alcohol decreases reaction times
Non-directional / two-tailed hypothesis
Hypothesises that there will be an effect but doesn't specify what it will be
Example: Alcohol will impact on reaction time
Qualitative research methodologies
For questions that can't be answered with scientific methods
Interviews, focus groups, observation
Investigate experiences, meanings, processes
Can be used to form testable hypotheses or to study particular issues that are unsuited to quantitative designs
Experiment
Used to determine cause-and-effect
Measure the effect of one variable on another
Cause-and-effect
How one variable affects another
Independent variable
Used in experiments
The variable that the researcher manipulates or changes
Dependent variable
The object/thing/result that the researcher measures after manipulating the independent variable
Within-subjects / repeated measures
Type of experiment
All participants are exposed to all levels or conditions of the independent variable
N
Number of participants in an experiment, sample size
Counter-balance
Dividing the participants of an experiment to do the levels in different orders to avoid order effects
Between subjects / independent designs
Type of experiment
Different people are exposed to different levels of the independent variable
Control group
The results of the experimental group are compared to those of a control group which was not exposed to the independent variable
The Hawthorne effect
A type of reactivity in which individuals modify an aspect of their behavior in response to their awareness of being observed
The placebo effect
Expectation effects result
Example: I expect the alcohol to slow my reaction time, therefore my reaction time is slowed
Single-blind
The participants of the experiment are unaware of which group they are in and which independent variable they have been exposed to
Prevents the placebo effect
Double-blind
Neither the participants of the experiment OR the researcher are aware of which subjects are in which groups and which independent variables they are exposed to
Prevents experimenter bias
Observational designs
Are not about establishing cause-and-effect
We don’t manipulate anything, we just measure existing behaviour/conditions
Used for studying topics where it would be difficult or unethical to manipulate conditions
Positive correlation
If one score increases so does the other
Example: Higher amounts of alcohol makes for better reaction times
Negative correlation
If one score increases the other decreases
Example: Higher amounts of alcohol makes the reaction time slower
Sample
Subsection of a population
Random sampling
Participants should be randomly assigned to avoid extraneous variables becoming confounds
Extraneous variables
Variables that will impact the experiment in some way and are unavoidable but that are outside of the researcher's control and not part of the variables which are being examined
For example: In the alcohol experiment, the person's age, tiredness levels, concentration, etc also impact on their reaction times
Confounds
When extraneous variables differ systematically by level of the independent variable
Convenience/opportunity sampling
Sampling from the most convenient subjects available, with limited randomness and variation, which often tends to not be representative of the whole population
Example: Conducting a psychology study where all the subjects are psychology students, though their area of study is irrelevant
Reliability
A test, study, or experiment will get the same results if it is repeated
Replication
Repetition of experiments and studies should be replicable in the sense that they should attain the same results if they are repeated
Validity
If the test is measuring what it is supposed to and is doing so accurately
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