Non-numeric argument to mathematical function

Question

I want to get pvalues from a data set. I have not had any problems to use pnorm, but I have now.

data(iris)

iris[,-5]<- scale(as.matrix(iris[,-5]))

# K-Means Cluster Analysis
fit <- kmeans(iris[,-5], 5) # 5 cluster solution
# get cluster means 
aggregate(iris[,-5],by=list(fit$cluster),FUN=mean)
# append cluster assignment
mydata <- data.frame(iris, fit$cluster)

pval<- pnorm(iris[,-5])

After this, I get message of "Error in pnorm(q, mean, sd, lower.tail, log.p) : Non-numeric argument to mathematical function".

What is the problem? I do not understand why this is happening.

Please let me know.

Answer 1

You are trying to pass a dataframe to a function that is requesting a numeric vector:

> is.numeric(iris[,-5])
[1] FALSE
> str(iris[,-5])
'data.frame':   150 obs. of  4 variables:
 $ Sepal.Length: num  -0.898 -1.139 -1.381 -1.501 -1.018 ...
 $ Sepal.Width : num  1.0156 -0.1315 0.3273 0.0979 1.245 ...
 $ Petal.Length: num  -1.34 -1.34 -1.39 -1.28 -1.34 ...
 $ Petal.Width : num  -1.31 -1.31 -1.31 -1.31 -1.31 ...

Try passing just a single column, like:

pnorm(iris[,1])