# [Rd] mean function on correlation matrices (PR#2540)

**Peter Dalgaard BSA
**
p.dalgaard@biostat.ku.dk

*Tue Feb 11 12:24:03 2003*

rs381@wbic.cam.ac.uk writes:
>* Full_Name: Raymond Salvador
*>* Version: R 1.6.2
*>* OS: Windows ME
*>* Submission from: (NULL) (131.111.93.195)
*>*
*>*
*>* The mean function applied on individual components of several correlation
*>* matrices
*>* gives a wrong result (gives the first value instead of the mean).
*>*
*>* Here there is a simple example
*>*
*>* x1 <- rnorm(10,1,1)
*>* y1 <- rnorm(10,1,1)
*>* z1 <- cbind(x1,y1)
*>* w1 <- cor(z1)
*>* x2 <- rnorm(10,1,1)
*>* y2 <- rnorm(10,1,1)
*>* z2 <- cbind(x2,y2)
*>* w2 <- cor(z2)
*>*
*>* w1[1,2]
*>* w2[1,2]
*>* mean(w1[1,2], w2[1,2])
*
Yes, and?
>* mean(2,6)
*[1] 2
>* mean(c(2,6))
*[1] 4
The mean function just doesn't work the way you expected. Please read
the help page before reporting bugs.
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907