Lesson 4 Correlations Flashcards
Correlations
Technique for analysing the strength of the relationship between two quantitative variables, known as co-variables
Correctional analysis will show one of three things
Positive correlation, Negative correlation and No Correlation
Positive Correlation
Means that as one variable increases the other variable increases as well
Negative Correlation
means that as one variable increases the other varibale decreases
No correlation
No relationship between the two variables
Facts about Correlations
The strength of a correlation can be between -1 and 1
A strong positive correlation coefficient will be a number closer to 1
0 means that there is no correlation
-1 means that there is a strong negative correlation
The strength of the correlation is known as the correlation coefficient
What are correlations plotted on
Scattergraph or a Scattergram
Advantages of Correlations
- Allows psychologists to establish the strength of the relationship between two variables and measure it precisely
- Allows researchers to investigate things that could not be manipulated experimentally for ethical and 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
- Cannot demonstrate cause and effect; we cannot tell which variable influences the other
- Even if there is a correlation it may be the case that the variables are not actually related but that there is a third unknown 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