Please see the FAQ: What's a reproducible example (`reprex`) and how do I do one? Using a reprex, complete with representative data will attract quicker and more answers. * This* question is more conceptual than coding, however, so it isn't strictly needed.

Let's consider the object returned by `plot`

. It's a two-dimensional representation of data along two axes, x and y. By convention, in `lm`

models the dependent variable is plotted along the x axis, so that it's possible to see the return value of the function `lm`

and its arguments.

This works well with a dependent variable for y and a single dependent variable for x. For every one unit increment of x what is the change in y is the question it answers.

But what happens with * six* independent variables, that have different scales

**plus**one is categorical and the others continuous?

Two dimensions won't cut it. The vector through 6-space is the trend line and that's difficult to show in 2-space.

In my admittedly limited understanding of intermediate to advanced multiple linear regression is that the alternative is to display the partial residuals piecewise.

A good resource (so far) for me Harrel's *Regression Modeling Strategies*.