# regr2.plot

##### 3D plot of z against x and y, with regression plane fit and display of squared residuals.

3D plot of z against x and y, with regression plane fit and display of squared residuals.

- Keywords
- models, regression

##### Usage

```
regr2.plot(x, y, z,
main.in="put a useful title here",
resid.plot=FALSE,
plot.base.plane=TRUE,
plot.back.planes=TRUE,
plot.base.points=FALSE,
eye=NULL, ## S-Plus
theta=0, phi=15, r=sqrt(3), ticktype="detailed", ## R
...)
```

##### Arguments

- x,y,z
See

- main.in
`main`

title for plot.- resid.plot
Argument to

`resid.squares`

.- plot.base.plane, plot.back.planes, plot.base.points
Should these items be plotted?

- eye
S-Plus only. See

- theta, phi, r, ticktype
R only. See

- …
Other arguments to

`persp`

.

##### Value

"Viewing Transformation" for projecting 3D coordinates (x,y,z)
into the 2D plane. See `persp`

for details.

##### Note

This plot is designed as a pedagogical example for introductory
courses. When `resid.plot=="square"`

, then we actually see the
set of squares for which the sum of their areas is minimized by the
method of "least squares". The demo called in the examples section
shows the geometry of regression coefficients, the change in predicted
y when x1 is changed one unit holding all other x variables constant.

##### References

Heiberger, Richard M. and Holland, Burt (2004b).
*Statistical Analysis and Data Display: An Intermediate Course
with Examples in S-Plus, R, and SAS*.
Springer Texts in Statistics. Springer.
ISBN 0-387-40270-5.

Smith, W. and Gonick, L. (1993).
*The Cartoon Guide to Statistics*.
HarperCollins.

##### See Also

##### Examples

```
# NOT RUN {
data(fat)
regr2.plot(fat[,"abdomin"], xlab="abdomin",
fat[,"biceps"], ylab="biceps",
fat[,"bodyfat"], zlab="bodyfat",
resid.plot="square",
eye=c(335.5, 115.65, 171.9), ## used only in S-Plus
theta=140, phi=35, r=sqrt(15), ## used only in R
box=is.R(),
plot.back.planes=FALSE,
main="Least-squares with two X-variables")
# }
# NOT RUN {
demo("regr2", package="HH", ask=FALSE)
## run the file manually to see the individual steps.
# }
```

*Documentation reproduced from package HH, version 3.1-40, License: GPL (>= 2)*