# Hello,
# I have a matrix that contains some missing values denoted by NA.
# I would like to calculate the mean for each column and not have the
# NA values included. here is a sample matrix "X" below.
c1 <- c(1,4,3,2,NA,2,5,6,4,2)
c2 <- c(1,3,6,NA,NA,2,9,6,1,2)
c3 <- c(2,4,2,NA,4,2,NA,6,3,5)
c4 <- c(2,6,4,NA,4,2,NA,6,1,5)
c5 <- c(2,3,2,NA,4,2,9,6,NA,5)
X<-cbind(c1,c2,c3,c4,c5)
X
# I have tried a variety of methods to calculate the Column means but each time
# i do not get the result i am looking for
result<-colMeans(X) # only returns a mean of NA
X <- X[!is.na(X)] # Effectively removes the NA values but now I
cannot calculate Column Means
# Below is the result of the column means I am looking for
result
c1 c2 c3 c4 c5
[1,] 3.22 3.75 3.5 3.75 4.125
# any help or ideas would be greatly appreciated
# thanks in advance
Luke Neraas
lukasneraas.r at gmail.com
University of Alaska Fairbanks
School of Fisheries and Ocean Sciences
11120 Glacier Highway
UAF Fisheries Division
Juneau, AK 99801