1. Exploratory Data Analysis 1.3. EDA Techniques 1.3.3. Graphical Techniques: Alphabetic 1.3.3.26. Scatter Plot 1.3.3.26.5. Scatter Plot: Quadratic Relationship
Scatter Plot Showing Quadratic Relationship
Discussion	Note in the plot above how no imaginable simple straight line could ever adequately describe the relationship between X and Y--a curved (or curvilinear, or non-linear) function is needed. The simplest such curvilinear function is a quadratic model for some A, B, and C. Many other curvilinear functions are possible, but the data analysis principle of parsimony suggests that we try fitting a quadratic function first.