R help - Nov 2008 - Linear regression

Hi List,
Does anybody know what function I need to use for a simple regression?

Here is the data: I want to find the value for x1=3.5
data<-data.frame(x=c(1:30),Value=c(31:60))
x1<-3.5

Regards,
Alireza

	[[alternative HTML version deleted]]

lm, for example:

fit1<-lm(y~x,data=mydata)

if you enter 
?lm 
in an R session you will get more information.
John

John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing)
>>> "Dr. Alireza Zolfaghari" <ali.zolfaghari at
gmail.com> 11/12/2008 3:56 PM >>>
Hi List,
Does anybody know what function I need to use for a simple regression?

Here is the data: I want to find the value for x1=3.5
data<-data.frame(x=c(1:30),Value=c(31:60))
x1<-3.5

Regards,
Alireza

	[[alternative HTML version deleted]]

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Alireza,

The "lm" function fits the linear regression (linear model), the
"predict" function predicts new response values based on values of the
predictor variables.

Try something like:
> mydata <- data.frame( x=1:30, y=31:60+rnorm(30) )
> fit1 <- lm( y ~ x, data=mydata )
> summary(fit1) # optional
> plot(fit1) # optional
> newdata <- data.frame(x=3.5)
> predict(fit1, newdata)
Also you should reread section 11 of "An Introduction to R" to get
more detail.

Hope this helps,

--
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 Dr. Alireza Zolfaghari
> Sent: Wednesday, November 12, 2008 1:57 PM
> To: R-help
> Subject: [R] Linear regression
>
> Hi List,
> Does anybody know what function I need to use for a simple regression?
>
> Here is the data: I want to find the value for x1=3.5
> data<-data.frame(x=c(1:30),Value=c(31:60))
> x1<-3.5
>
> Regards,
> Alireza
>
>         [[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.