Getting “NA” when I run a standard deviation

Question

Quick question. I read my csv file into the variable data. It has a column label var, which has numerical values.

When I run the command

Answer 1

You probably have missing values in var, or the column is not numeric, or there's only one row.

Try removing missing values which will help for the first case:

sd(dat$var, na.rm = TRUE)

If that doesn't work, check that

class(dat$var)

is "numeric" (the second case) and that

nrow(dat)

is greater than 1 (the third case).

Finally, data is a function in R so best to use a different name, which I've done here.