• Correlation analysis is concerned with measuring the strength (degree of association) and direction (positive or negative) of the relationship between variables. – No causal relationship is implied. • Regression analysis is helpful in assessing specific forms of the relationship between variables. The ultimate objective is to predict or estimate the value of one variable corresponding to a given value of another variable. – Causal relationship is believed to exist. Pharmaceutical Biostatistics: Correlation & Regression
If you can tell which variable goes on the y-axis, then you know whether to use correlation or regression.
• Correlation: it does not matter which variable is on the y-axis • No hypothesized cause and effect relationship between variables
Pharmaceutical Biostatistics: Correlation & Regression
n Potential response variable (dependent) on y-
axis; explanatory or predictor variable (independent) on x-axis