Psychology - Research Methods - Correlations, Aims and Hypothesis Flashcards
Correlations
Strength of a relationship between to co-variables (quantitative variables)
Positive correlation
as one variable increases, so does the other
Negative correlation
as one variable increases, the other decreases
No correlation
There is no relationship between data sets.
What can the strength of correlation be?
Can be between -1 and +1
Correlation coefficient
The strength of a correlation
Advantages of correlations
- Allows psychologists to establish strength of a relationship between two variables - Allows researchers to investigate things that could not be manipulated experimentally for ethical or practical reasons - Allows predictions to be made about one of the variables based on the other
Disadvantages of correlations
- Cannot demonstrate cause and effect - Correlation may be the impact of an unknown third variable - Can only measure linear relationships and doesn’t detect curvilinear relationships
Aim
Precise statement of the purpose of a study
Hypotheses
Precise, testable statement about the expected outcome of an investigation
null hypothesis
IV will have no effect on the dependent variable
alternative hypothesis
IV will have an effect on the DV
Non-directional hypothesis (two tailed)
Does not state the direction of the predicted differences between conditions
Directional hypothesis (one-tailed)
States the direction of the predicted difference between conditions
Curvilinear relationship
A type of relationship between two variables where as one variable increases so does the other, but only up to a certain point after which the other decreases
