Question

Function is as below:

calculateMeanVar <- function(x) {

x_mean <- mean(x)

x_var <- var(x)

return(data.frame(xmean = x_mean, xvar = x_var))

}

Now, test you function on the petal length of iris data set (Built in data set in R):

- Include standard error in the function

- Include the standard error in the output of the function (i.e., in the return() portion).

Answer 1

Rcode:

to get the standard error=standard deviation/sqrt(sample size),use sd function and length function.

calculateMeanVar <- function(x) {
  
x_mean <- mean(x)
  
x_var <- var(x)
x_sd <- sd(x)
x_len <- length(x)
x_SE <- x_sd/sqrt(x_len)
  
return(data.frame(xmean = x_mean, xvar = x_var,xSE=x_SE))
  
}

To test the above function on iris petal length:

calculateMeanVar(iris$Petal.Length)

Output:

petal length standard error=0.144136