[R] summary statistics into table/data base, many factors to analyse

Gerit Offermann gerit.offermann at gmx.de
Thu Nov 20 15:16:50 CET 2008

Dear list,

I reduced my data to the following:

x <- c(1,4,2,6,8,3,4,2,4,5,1,3)
y <- as.factor(c(2,2,1,1,1,2,2,1,1,2,1,2))
z <- as.factor(c(1,2,2,1,1,2,2,3,3,3,3,3))

I can produce the statistical summary just fine.
s1 <- tapply(x, y, summary)
d1 <- tapply(x, y, sd)
s2 <- tapply(x, z, summary)
d2 <- tapply(x, z, sd)

First thing:
I have 100 plus factors to analyse. Theirs names are f1001 to f1381 (about).
Is there a way to avoid having to write these lines 100 plus times?

Second thing:
How can I put the standard deviation and the summary statistics into one output?

Third thing:
In the end I want to write the summary statistics into a data base (Access). It would be fantastic if I could achieve a table such as:

factor  level  Min. 1st Qu.  Median    Mean 3rd Qu.    Max.   SDev.
y         1   1.000   2.000   3.000   3.833   5.500   8.000  2.714160
y         2   1.000   3.000   3.500   3.333   4.000   5.000  1.366260
z         1   1.0       3.5       6.0      5.0       7.0      8.0     3.6055513

I tried to unlist the matrices, but it did not help much.
it <- NULL # "it" - Iterationen

for (i in 1:nlevels(z)){
     it[[i]] <- unlist(s1[[i]])}

Help to any of the three points is greatly appreciated.


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