Quantitative Data Types

Quantitative data are numerical and can be classified as discrete if they result from counting or continuous if they result from measuring.

Opening

A hospital administrator must decide whether to record patient ages as whole years or as exact birth dates. The choice determines whether the data are discrete or continuous, which affects how they can be analyzed.

The idea

Quantitative data are numerical and are classified as discrete if they come from counting or continuous if they come from measuring.

Vocabulary· 2 terms

Worked example

You go to the supermarket and purchase three cans of soup, two packages of nuts, four kinds of vegetables, and two desserts. The weights of the soups are 19 ounces, 14.1 ounces, and 19 ounces.

1
Count the items: three cans of soup, two packages of nuts, four kinds of vegetables, and two desserts.
Counting produces whole numbers, which are discrete data.
2
Measure the weights of the soups: 19 ounces, 14.1 ounces, and 19 ounces.
Measuring produces values that can be as precise as the instrument allows, which are continuous data.
3
Identify the types of soups, nuts, vegetables, and desserts.
Types are categories, not numbers, so they are qualitative data.

The counts are quantitative discrete, the weights are quantitative continuous, and the types are qualitative.

Discrete versus continuous data

Identifying Data Types

Data that are discrete often start with the words "the number of." For example, the number of pairs of shoes you own is discrete, while the distance from your home to the nearest grocery store is continuous.

Easily confused

Looks like

The number of students in a class and the time it takes to run a mile both seem like numbers.

Actually

The number of students is discrete because you count them; the time is continuous because you measure it.

Counting gives whole numbers with gaps between them, while measuring gives values that can be subdivided infinitely.

Apply the concept to a new scenario.

Recap

Say each point to yourself, then tap it to check.

Quantitative discrete data result from counting.
Quantitative continuous data result from measuring.

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Source

Barbara Illowsky and Susan Dean

Licensed under CC BY 4.0. This course is an adaptation, not the original work.

Access for free at openstax.org/details/books/introductory-statistics-2e