# Quantitative Data

Quantitative data, also known as continuous data, consists of numeric data that support arithmetic operations. This is in contrast with qualitative data, whose values belong to pre-defined classes with no arithmetic operation allowed. We will explain how to apply some of the R tools for quantitative data analysis with examples.

The tutorials in this section are based on a built-in data frame named faithful. It consists of a collection of observations of the Old Faithful geyser in the USA Yellowstone National Park. The following is a preview via the head function.

eruptions waiting

1 3.600 79

2 1.800 54

3 3.333 74

4 2.283 62

5 4.533 85

6 2.883 55

There are two observation variables in the data set. The first one, called eruptions, is the duration of the geyser eruptions. The second one, called waiting, is the length of waiting period until the next eruption. It turns out there is a correlation between the two variables, as shown in the Scatter Plot tutorial.