1. 1 Press Ctrl-A ©G Dear 2009 – Not to be sold/Free to use CorrelationCoefficient Stage 6 - Year 11 General Mathematics HSC

2. 2 Correlation Coefficient (1/2) 1.The scatter plot shows the quality of the relationship (correlation) between two variables. -0.75 -0.5 -0.25 0 0.25 0.5 0.75 1 Strong Positive Correlation  Moderate Positive Correlation  Weak Positive Correlation  { No Correlation  Weak Negative Correlation  Moderate Negative Correlation  Strong Negative Correlation  2.When one variable increases and the other variable increases then there is a positive correlation. 3.When one variable increases and the other variable decreases then there is a negative correlation. NOT 4.Strong correlation coefficients does NOT mean that one variable caused the other.

3. 3 Correlation Coefficient (2/2) 0.75  1 Strong Positive Correlation 1 Perfect Positive Correlation 0.5  0.75 Moderate Positive Correlation 0.25  0.5 Weak Positive Correlation -0.25  0.25 No Correlation -0.25  -0.5 Weak Negative Correlation -0.5  0.75 Moderate Negative Correlation -0.75  -1 Strong Negative Correlation - 1 Perfect Negative Correlation