In these lessons, we will learn how to differentiate between first-hand and second-hand data. We will learn how to draw and interpret double bar graphs.

## First-Hand Data and Second-Hand Data

Differentiate between first-hand and second-hand data.
First-hand data is data that you collect yourself.
Second-hand data is data that is collected by someone else.

First-Hand Data
• Data collected by the researcher (in school, this is the student)
• Observations, surveys, experiments
• Student primary source
• Questions created should help give more precise answers

Second-Hand Data
• Data collected by others and used for secondary analysis
• Found in news, Internet, statistics
• Student not part of data collections or questioning
• Can create questions based on data

First hand vs second hand data.

## Double Bar Graph

A double bar graph is best used to show how two sets of data are different or alike.

In a double bar graph:
• Each set of data must use the same scale
• All graphs must have a title, scale and legend.
• The order of colors must remain the same throughout.

An example is presented below. Five students in the class have been asked how many brothers and sisters they have.

Drawing double bar graphs

Interpreting double bar graphs.

Double Bar Graphs.

Double Bar Graphs
Learn to make and interpret double bar graphs.

Rotate to landscape screen format on a mobile phone or small tablet to use the Mathway widget which allows your to practice solving Algebra, Trigonometry, Calculus and other math topics.

You can use the Mathway widget below to practice Statistics or other math topics. Try the given examples, or type in your own problem. Then click "Answer" to check your answer.