|C1||Wear and tear after 8 hours of operation (in tenths of a mm)|
|C2||Rotation speed (in rpm)|
|C3||Type of steel (encoded as 0 and 1)|
As always, we start with an exploratory analysis of the data:
Graph > Matrix Plot > Matrix of plots: Simple
Looking at the Matrix Plot, we can rule out the presence of anomalous values. Regarding the relations among the variables, we see that a higher speed is associated with a major wear, and that material 1 wears out more than material 0.
In this case, it is also a good idea to draw a scatterplot of wear versus speed stratified according to the material.
Graph > Scatterplot: With Groups
We can clearly see the relation between wear and speed as well as that material 1 wears out more than material 0. We compute the equation of the regression model:
Stat > Regression > Regression
Since the type of material is a categorical ...