# Types of data

## Key points

- Types of data include
**continuous**,**discrete**and**categoric.**

- Classifying a variable as a particular type of data is important when considering how to present the data.

- Data can be presented in a number of ways, which depends on the type of variable and the uses.

**How do scientists collect data to help answer questions?**

Scientists collect data from carrying out experiments and investigations.

### Video

Watch this video about how to identify continuous and discrete data.

## Types of data

In science, investigations involve the collection of data. The data collected can be or .

Data collected can be:

- - numeric data can have any value within a range. Examples include time, height and temperature.
- - numeric data that can only have certain values. Examples include shoe size, number of people in a room and the number of marks on a test.
- - the data are words. Examples include colour such as ‘red’ or ‘blue’, and how an object feels like, eg: ‘rough’ or ‘smooth’.

During an experiment, the effect of one on another is tested. There are three types of variable:

**Independent**- a variable that is changed during an experiment.**Dependent**- a variable that is measured or tested during an experiment. This depends on the independent variable.**Control**- a variable, other than the independent variable, that could affect the dependent variable. A control variable is something you keep the same.

The variable that is measured - the dependent variable - is often measured as continuous data, but this is not always the case.

- For example, in an experiment to find out how the temperature of a liquid decreased over time, temperature is the dependent variable and is continuous.
- But in an investigation into eye colour, the number of people is the dependent variable and the data is discrete.

Independent variables can be categoric or continuous.

- An example of categoric data would be ‘choice of food for lunch’ and 'counting the number of people who chose certain foods'.
- An example of continuous data would be 'temperature': when changing the temperature of water, see how quickly sugar dissolves into it.

**True or false?**

**Dependent variables can be continuous or discrete.**

True.

## How to present data

The method of presentation depends on:

- The type of variable.
- The reason for presenting the data, eg to sort/ compare/ show a pattern.

Below are ways of presenting data:

Ways of presenting data | Uses |
---|---|

Table | To show data in an order, eg biggest to smallest number. Also used to record results during an experiment. |

To find a link between variables. Both variables are quantitative and could be discrete or continuous. A scatter graph is a line graph but without the line joining the points. | |

To show how the dependent variable affects the independent variable. Both variables are continuous. The points are joined with a line of best fit, which is straight or a smooth curve. | |

To compare sets of data. The independent variable is usually discrete and the dependent variable is quantitative. | |

To show proportions of a total. The independent variable is discrete or categoric. Often used when showing percentages of data. |

**The way in which data is presented depends on the reason for presenting data, and what else?**

The type of variable.