(1 + 2 + 3 + 4 + 5) / 5[1] 3R Functions
Essentially all of your R-based analyses will revolved around calling functions to manipulate the contents of objects stored in the environment and saving those modified objects as new objects.
Suppose I want to calculate the average of the first five positive integers, \(\{1, 2, 3, 4, 5\}\). I could directly apply the formula for the mean using nothing but basic arithmetic operators.
Of course, we won’t get very far with any real-world data analysis if we need to explicitly write out the formula for every single estimate we make. So, we typically call a pre-existing function to do the estimation. The following code calls the mean() function to calculate the average of the values contained in the numeric vector, \([1, 2, 3, 4, 5]\), that we’ve created with the : operator (which is also a kind of function).
mean(1:5)[1] 3