[R] linear regression

[Mikhail Titov]

Don't forget to load `lattice` package. `latticeExtra` with
`panel.ablineeq` can be also helpful.

This was however for plotting. For subset regression by each WR without
plotting you'd use something like `lapply` or `sapply`.

ans <- sapply(unique(data$WR), function(dir) {
    out <- list(lm(PM10~Ref, subset(data, WR=dir)))
    names(out) <- dir
    out
})

`ans$West` will return one of the results.

There are many ways to skin a cat. Perhaps it was not the best one.

Mikhail

On 08/13/2011 11:30 AM, Dennis Murphy wrote:
> Hi:
>
> Try something like this, using dat as the name of your data frame:
>
> xyplot(PM10 ~ Ref | WR, data = dat, type = c('p', 'r'))
>
> The plot looks silly with the data snippet you provided, but should
> hopefully look more sensible with the complete data. The code creates
> a four panel plot, one per direction, with points and a least squares
> regression line fit in each panel. The regression line is specific to
> a data subset, not the entire data frame.
>
> HTH,
> Dennis
>
> On Sat, Aug 13, 2011 at 5:43 AM, maggy yan <kiotoqq at googlemail.com> wrote:
>> dear R users,
>> my data looks like this
>>
>>         PM10       Ref   UZ     JZ         WT   RH   FT   WR
>> 1   10.973195  4.338874 nein Winter   Dienstag   ja nein West
>> 2    6.381684  2.250446 nein Sommer    Sonntag nein   ja  Süd
>> 3   62.586512 66.304869   ja Sommer    Sonntag nein nein  Ost
>> 4    5.590101  8.526152   ja Sommer Donnerstag nein nein Nord
>> 5   30.925054 16.073091 nein Winter    Sonntag nein nein  Ost
>> 6   10.750567  2.285075 nein Winter   Mittwoch nein nein  Süd
>> 7   39.118316 17.128691   ja Sommer    Sonntag nein nein  Ost
>> 8    9.327564  7.038572   ja Sommer     Montag nein nein Nord
>> 9   52.271744 15.021977 nein Winter     Montag nein nein  Ost
>> 10  27.388416 22.449102   ja Sommer     Montag nein nein  Ost
>>
>> .
>>
>> .
>>
>> .
>>
>> .
>>
>> til 200
>>
>>
>> I'm trying to make a linear regression between PM10 and Ref for each of the
>> four WR, I've tried this:
>> plot(Nord$PM10 ~ Nord$Ref, main="Nord", xlab="Ref", ylab="PM10")
>> but it does not work, because "Nord cannot be found"
>> what was wrong? how can I do it? please help me
>>
>>        [[alternative HTML version deleted]]
>>
>>
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>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
> ______________________________________________
> 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.