Correlations Flashcards
Correlations
Correlations are a technique for analysing the strength of the relationship between two quantitative variables, known as co-variables. The data for a correlation is usually obtained from a non experimental source, such as a survey.
Analysis of correlation will show one of three things
Positive correlation
Negative correlation
No correlation
Positive correlation
A Positive correlation means that as one variable increases the other variable increases as well.
Negative correlation
A negative correlation means that as one variable increases the other variable decreases.
No correlation
There is no relationships between the two variables at all.
Rules of correlation
The strength of a correlation can be between -1 and 1. Zero means that there is no correlation. -1 means that there is a strong negative correlation. +1 means that there is a strong positive correlation. The strength of the correlation is known as the correlation coefficient.
Advantages of correlations
- This technique does allow psychologists to establish the strength of the relationship between two variables and measure it precisely.
- This technique also allows researchers to investigate things that could not be manipulated experimentally for ethical or practical reasons.
- Once a correlation has been conducted predictions can be made about one of the variables based on what is known about the other variable.
Disadvantages of correlations
- Correlational analysis cannot demonstrate cause and effect; we cannot tell which variable influences the other.
- Even if there is a correlation between two variables it may be the case that the variables are not actually related but that there is a third unknown variable which influences both (confounding variable)
- Correlations can only measure linear relationships and does not detect curvilinear relationships. This is when there is a positive relationship up to a certain point but after that the relationship becomes negative or vice versa.