One axis represents each variable, data plotted as points
Response /Dependent variable
measures or records the outcome (y-axis)
Explanatory /Independent variable
explains changes in the response variable (x-axis)
linear, non-linear, no relationship, curved, clustered
positive, negative, no direction
how much scatter around the main form
deviations from the main pattern
- Correlation coefficient (r) - a measure of the direction and strength of a relationship. It is
- calculated using the mean and the standard deviation of both the x and y variables.
- r ranges from -1 to +1
- When variability in one or both variables decreases, the correlation coefficient gets
- stronger (closer to +1 or −1).
- Correlations are calculated using means and standard deviations and thus are NOT
- resistant to outliers.