CODEWITHSUNDEEP
r
lucasfaztudo
lucasfaztudo

Reputation: 13

Calculate population standard deviation of a column

I want to know the standard deviation of every column i have in a data frame. Right now i'm using the formula

apply(df,2,sd)

But it's showing me the sample standard deviation, what is the way to find the population standard deviation in this scenario?

Upvotes: 0

Views: 338

Answers (1)

Jon Spring
Jon Spring

Reputation: 66480

We can define the calculation for population standard deviation:

sd.p=function(x){sd(x)*sqrt((length(x)-1)/length(x))}
# From  https://stackoverflow.com/a/66349386/6851825

And then use your formulation:

apply(mtcars,2,sd.p)
        mpg         cyl        disp          hp        drat          wt        qsec          vs 
  5.9320296   1.7577951 121.9867814  67.4830708   0.5262581   0.9630477   1.7588006   0.4960784 
         am        gear        carb 
  0.4911323   0.7261844   1.5897622

From other answers in that question it looks like there is not a built-in function for this in base R, but a number of packages include a function to that effect: https://stackoverflow.com/a/59120744/6851825

Upvotes: 2

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