On 09 Jun 2004 09:52:27 -0400, Paulo Nuin <[EMAIL PROTECTED]> wrote :
>Hello everyone > >This is my first message to the list and I believe the question I am >including is a simple one. > >I have a matrix where I need to calculate ANOVA for the rows as the >columns represent a different treatment. I would like to know if there >is a command or a series of commans that I can enter to do that. > >At the moment I have a external script that extracts each row from the >matrix, transforms it in a column, another factor columns is add and the >text file is thrown to Rterm --vanilla. Welcome to the list. One suggestion: you should use a subject line that matches the topic of your question, or your question is likely to get lost. Most of the modelling functions in R assume that data is in a vector. You can convert a matrix to a vector using the as.numeric() function. To get the treatments associated with each one, you could apply as.numeric() to the col() function. You should also convert this to a factor, for the anova. For example, > original <- matrix(1:12, 3, 4) > vector <- as.numeric(original) > treatments <- as.factor(as.numeric(col(original))) > vector [1] 1 2 3 4 5 6 7 8 9 10 11 12 > treatments [1] 1 1 1 2 2 2 3 3 3 4 4 4 Levels: 1 2 3 4 > anova(lm(vector ~ treatments)) Analysis of Variance Table Response: vector Df Sum Sq Mean Sq F value Pr(>F) treatments 3 135 45 45 2.356e-05 *** Residuals 8 8 1 --- Signif. codes: 0 `***' 0.001 `**' 0.01 `*' 0.05 `.' 0.1 ` ' 1 You can read the help pages on each of these functions to see what options are available. Duncan Murdoch ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html