Getting "NA" when I run a standard deviation

r statistics na stdev
evt picture evt · Apr 21, 2011 · Viewed 40.1k times · Source

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 

sd(data$var)

I get 

[1] NA

instead of my standard deviation.

Could you please help me figure out what I am doing wrong?

Answer

nzcoops picture nzcoops · Apr 21, 2011

Try sd(data$var, na.rm=TRUE) and then any NAs in the column var will be ignored. Will also pay to check out your data to make sure the NA's should be NA's and there haven't been read in errors, commands like head(data), tail(data), and str(data) should help with that.

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