1. Lesson 2: Correlational Analysis1

2. Correlational Analysis
This is a technique for analysing data.
It measures the strength of the relationship between two quantitative variables. 2

3. Positive correlation means that as one variable increases the other variable increases as well.
A negative correlation means that as one variable increases the other variable decreases. 3

4. The strength of a correlation can be between -1 and 1.
0 means that there is no correlation.
-1 means that there is a strong negative correlation.
1 means that there is a strong positive correlation. 4

5. Advantages
This technique does allow psychologists to establish the strength of the relationship between two variables and measure it precisely. 5

6. This technique also allows researchers to investigate things that could not be manipulated experimentally for ethical or practical reasons. 6

7. Disadvantages
Correlational analysis can not demonstrate cause and effect, we can not tell which variable influences the other.
It may be that a third unknown variable influences both. 7

8. Correlation can only measure linear relationships and can not detect curvilinear relationships.8

9. Ethical Issues
Data used in correlations is often collected without the people whose data it is being aware of it. 9

10. Informed consent can not be obtained and a participant cannot ask for their data to not be used, which violates their right to withdraw.
In some cases this data may even have been given for confidential purposes. 10