R help - Aug 2010 - plot the dependent variable against one of the predictors with other predictors as constant

Hi, folks,

Happy work in weekends >_<

My question is how to plot the dependent variable against one of the
predictors with other predictors as constant. Not for the original data, but
after prediction. It means y is the predicted value of the dependent
variables. The constane value of the other predictors may be the average or
some fixed value.

#######
y=1:10
x=10:1
z=2:11
lin_model=lm(z~x+y)
x_new=11:2
#######


How to plot predicted value of z from the regression model with x takes
x_new and y as a constant (let's say y=1)


I am thinking about using 'predict' command to generate the prediction
of z
with the new data.frame but there should be a better way.

Thanks all.

Yi

	[[alternative HTML version deleted]]

There are many ways to do this.  Here is one.

install.packages('rms')
require(rms)
dd <- datadist(x, y); options(datadist='dd')
f <- ols(z ~ x + y)
plot(Predict(f))    # plot all partial effects
plot(Predict(f, x)) # plot only the effect of x
plot(Predict(f, y)) # plot only the effect of y
f <- ols(z ~ pol(x,2)*pol(y,2) # repeat, not assuming linearity

Frank E Harrell Jr   Professor and Chairman        School of Medicine
                      Department of Biostatistics   Vanderbilt University

On Sat, 7 Aug 2010, Yi wrote:
> Hi, folks,
>
> Happy work in weekends >_<
>
> My question is how to plot the dependent variable against one of the
> predictors with other predictors as constant. Not for the original data,
but
> after prediction. It means y is the predicted value of the dependent
> variables. The constane value of the other predictors may be the average or
> some fixed value.
>
> #######
> y=1:10
> x=10:1
> z=2:11
> lin_model=lm(z~x+y)
> x_new=11:2
> #######
>
>
> How to plot predicted value of z from the regression model with x takes
> x_new and y as a constant (let's say y=1)
>
>
> I am thinking about using 'predict' command to generate the
prediction of z
> with the new data.frame but there should be a better way.
>
> Thanks all.
>
> Yi
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

> I am thinking about using 'predict' command to generate the
prediction of z
> with the new data.frame but there should be a better way.
I'm puzzled. Why would you think that? This is the canonical way to do
predictions in R.

Bert Gunter
Genentech Nonclinical Statistics

Look at the TkPredict and Predict.Plot functions in the TeachingDemos package as
a couple of options.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Yi
> Sent: Saturday, August 07, 2010 3:13 PM
> To: R (r-help at R-project.org)
> Subject: [R] plot the dependent variable against one of the predictors
> with other predictors as constant
> 
> Hi, folks,
> 
> Happy work in weekends >_<
> 
> My question is how to plot the dependent variable against one of the
> predictors with other predictors as constant. Not for the original
> data, but
> after prediction. It means y is the predicted value of the dependent
> variables. The constane value of the other predictors may be the
> average or
> some fixed value.
> 
> #######
> y=1:10
> x=10:1
> z=2:11
> lin_model=lm(z~x+y)
> x_new=11:2
> #######
> 
> 
> How to plot predicted value of z from the regression model with x takes
> x_new and y as a constant (let's say y=1)
> 
> 
> I am thinking about using 'predict' command to generate the
prediction
> of z
> with the new data.frame but there should be a better way.
> 
> Thanks all.
> 
> Yi
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.