# [R] Problems plotting and regression w.r.t. date data type on x axis

Kategoricus residual at users.sourceforge.net
Thu Feb 14 10:10:23 CET 2013

```Hello,

probably a newbie question, but i didnt find any information on
plotting/regressing w.r.t. a date data type. My trials were unfruitful. Can
anyone help ? Thanks in advance!

Here is my interaction with R:

> tabelle
date number date2
1 2009-01-1 1673 2009-01-01
2 2009-12-1 2111 2009-12-01
3 2010-7-1 2487 2010-07-01
4 2013-2-1 4301 2013-02-01
> regression.punkte<-lm(tabelle\$number ~ tabelle\$date2)
Fehler in model.frame.default(formula = tabelle\$number ~ tabelle\$date2, :
ungültiger Typ (list) für die Variable 'tabelle\$date2'
> regression.punkte<-lm(tabelle\$number ~ tabelle\$date)
> plot(tabelle\$date2,tabelle\$number, pch=19, xlab="date of retrieval",
> ylab="number of animals") ***R DRAWS THIS***
> regression.punkte

Call:
lm(formula = tabelle\$number ~ tabelle\$date)

Coefficients:
(Intercept) tabelle\$date2009-12-1 tabelle\$date2010-7-1
1673 438 814
tabelle\$date2013-2-1
2628

> abline(regression.punkte, lwd=2) ***R DOES NOT DRAW LINE***
Warnmeldung:
In abline(regression.punkte, lwd = 2) :
nutze nur die ersten beiden von 4 Regressionskoeffizienten
> summary(regression.punkte)

Call:
lm(formula = tabelle\$number ~ tabelle\$date)

Residuals:
ALL 4 residuals are 0: no residual degrees of freedom!

Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 1673 NA NA NA
tabelle\$date2009-12-1 438 NA NA NA
tabelle\$date2010-7-1 814 NA NA NA
tabelle\$date2013-2-1 2628 NA NA NA

Residual standard error: NaN on 0 degrees of freedom
Multiple R-squared: 1, Adjusted R-squared: NaN
F-statistic: NaN on 3 and 0 DF, p-value: NA

--
View this message in context: http://r.789695.n4.nabble.com/Problems-plotting-and-regression-w-r-t-date-data-type-on-x-axis-tp4658518.html
Sent from the R help mailing list archive at Nabble.com.

```