#Intro to statistics with R

Arrays in R start from 1, not from 0

From the paper: On theory of measurement.

Used to assign individual cases to categories. Differentiate one class form another.

Used to rank elements in a dataset.

Rank order cases where the distance, or interval, between each value is equal. Longirut and latitude

Like interval, but they have a true zero point. For example temperature like kelvin scale.

This concept is important in R because some variables can be treated differently For example:

fam<-c(2, 3, 5, 7, 11, 13, 17)
class(fam)
[1] "numeric"
fam_factor <- factor(fam)
class(fam_factor)
[1] "factor"

Now fam_factor becomes a nominal variable instead of numbers, and now we can name a class with an instance of fam_vector