Refactoring: functions
Copying and pasting once is OK, but three times usually suggests something is wrong.
The provided code calculates an approximate 95% confidence interval for the variables x and y.
This exercise is part of the course
Defensive R Programming
Exercise instructions
- Create a function called
ci(), taking a single argument calledvalueswith no default values. - Get the function to return the 95% confidence interval.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
n <- length(x); m <- mean(x); s <- sd(x)
c(m - 1.96 * s / sqrt(n), m + 1.96 * s / sqrt(n))
n <- length(y); m <- mean(y); s <- sd(y)
c(m - 1.96 * s/sqrt(n), m + 1.96 * s/sqrt(n))
# Define a function to prevent pasting the code above
ci <- function(values) {
n <- length(values)
m <- ___
s <- ___
c(m - ___, m + ___)
}