[R] Summary shows wrong maximum

[Gavin Simpson]

On Mon, 2006-12-04 at 12:04 +0100, Sebastian Spaeth wrote:
> Hi all,
> I have a list with a numerical column "cum_hardreuses". By coincidence I  
> discovered this:
> 
> > max(libs[,"cum_hardreuses"])
> [1] 1793
> 
> > summary(libs[,"cum_hardreuses"])
>     Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
>        1       2       4      36      14    1790
> 
> (note the max value of 1790) Ouch this is bad! Anything I can do to remedy  
> this? Known bug?

Did you read ?summary, which has:

 ## Default S3 method:
     summary(object, ..., digits = max(3, getOption("digits")-3))

so this is a rounding issue of the *printed* representation of the
summary. Just change digits to be a larger number:

> dat <- rnorm(100)
> max(dat)
[1] 2.434443
> summary(dat)
    Min.  1st Qu.   Median     Mean  3rd Qu.     Max.
-2.21100 -0.65450  0.03793  0.06919  0.84650  2.43400
> summary(dat, digits = 10)
       Min.     1st Qu.      Median        Mean     3rd Qu.        Max.
-2.21106232 -0.65451716  0.03793040  0.06919486  0.84652269  2.43444263
> # same with integer as in your example
> dat <- floor(dat * 1000000)
> max(dat)
[1] 2434442
> summary(dat)
    Min.  1st Qu.   Median     Mean  3rd Qu.     Max.
-2211000  -654500    37930    69190   846500  2434000
> summary(dat, digits = 10)
       Min.     1st Qu.      Median        Mean     3rd Qu.        Max.
-2211063.00  -654517.50    37930.00    69194.38   846522.00  2434442.00

HTH

G

> 
> This is a Version 1.16 (3198) of the MacOSX R.
> 
> Regards,
> Sebastian Spaeth
> 
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