### Learning Outcomes

- Determine whether a value calculated from a group is a statistic or a parameter
- Identify the difference between a census and a sample
- Identify the population of a study
- Determine whether a measurement is categorical or qualitative

## Quantitative or Categorical

Once we have gathered data, we might wish to classify it. Roughly speaking, data can be classified as categorical data or quantitative data.

### Quantitative and categorical data

**Categorical (qualitative) data** are pieces of information that allow us to classify the objects under investigation into various categories.

**Quantitative data** are responses that are numerical in nature and with which we can perform meaningful arithmetic calculations.

### example

We might conduct a survey to determine the name of the favorite movie that each person in a math class saw in a movie theater.

When we conduct such a survey, the responses would look like: *Finding Nemo*, *The Hulk*, or *Terminator 3: Rise of the Machines*. We might count the number of people who give each answer, but the answers themselves do not have any numerical values: we cannot perform computations with an answer like “*Finding Nemo*.” Is this categorical or quantitative data?

### Example

A survey could ask the number of movies you have seen in a movie theater in the past 12 months (0, 1, 2, 3, 4, . . .). Is this categorical or quantitative data?

Sometimes, determining whether or not data is categorical or quantitative can be a bit trickier. In the next example, teh data collected is in numerical form, but it is not quantitative data. Read on to find out why.

### example

Suppose we gather respondents’ ZIP codes in a survey to track their geographical location. Is this categorical or quantitative?

### Example

A survey about the movie you most recently attended includes the question “How would you rate the movie you just saw?” with these possible answers:

1 – it was awful

2 – it was just OK

3 – I liked it

4 – it was great

5 – best movie ever!

Is this categorical or quantitative?

The examples in this page are discussed further in the following video:

### Try It

Classify each measurement as categorical or quantitative.

- Eye color of a group of people
- Daily high temperature of a city over several weeks
- Annual income