[R] Is this correct?

[John Kane]

You need to do the homework yourself.  What is correct depends on what the data says,(and what exactly the prof wants). :)  The best idea probably is to decide yourself on what you want to present and write a rationale as to why you chose this analysis.

More generally there is a lot of good documentation available on the R website although it is not always easy to get to.  Try going to the R home page http://www.r-project.org/, then choose Other (left side of page) and then select contributed documentation.  

Something like “Using R for Data Analysis and Graphics - Introduction, Examples and Commentary” by John Maindonald or “Kickstarting R (version 1.6)” compiled by Jim Lemon should be helpful for ploting among other things.

Have fun.


--- On Sun, 11/23/08, Rlover <lmoto001 at fiu.edu> wrote:

> From: Rlover <lmoto001 at fiu.edu>
> Subject: [R]  Is this correct?
> To: r-help at r-project.org
> Received: Sunday, November 23, 2008, 9:45 PM
> I have to answer the following question for a homework
> assignment.
> 
> A researcher was interested in whether people taking part
> in sports at
> university made more money after graduating, taking into
> account the
> students' GPA. They sampled 200 alumni from a large
> university. The
> variables are: income (income 10 years after graduating),
> sports (1 if they
> did sports, 0 if they did not), and GPA (the grade point
> average at
> university). Discuss the relationship between taking part
> in sports, GPA,
> and income for these data. 
> 
> 
> The R code I used so far is
> 
> Does sports predict GPA? 
> 
> > lm1<-lm(GPA~sports)
> > summary(lm1)
> 
> Does sports predict income? 
> > lm2<-lm(income~sports)
> > summary(lm2)
> 
> Does GPA predict income? 
> > lm3<-lm(income~GPA)
> > summary(lm3)
> 
> Does sports predict income after accounting for GPA? 
> > lm4<-lm(income~GPA+sports)
> > summary(lm4)
> 
> 
> Can someone let me know is the above is correct? I am not
> sure if to keep
> all four regressions or only 1 and 4. Also, I need to plot
> the data on a
> graph or table. Can anyone suggest how to do this? Thank
> you in advance :)
> 
> 
> -- 
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> 
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