Interpret secondary data presented in digital media and elsewhere (ACMSP148)

LO: To interpret secondary data


  • What secondary data is

  • What is the difference between secondary data and primary data

  • How to read a graph and interpret the results.


  • That data when collected from secondary sources may not be entirely accurate.


  • I can read secondary data.

Teacher Notes

Types of Data

Primary data is information that is collected from the surveyor or yourself. This gives you more accurate first-hand data because you collected the data yourself.

Secondary data is information that is collected from someone else. It is impossible to go around collecting data for absolutely everything, which is why statisticians sometimes need to rely on others in order to obtain data. The positive of this is that you don’t have to spend time in order to collect data for yourself. The drawback, however, is that secondary data collected may not be entirely accurate.

Different Data Types

This is a dot plot. Each dot represents 1 object surveyed. In some instances, dots can be worth multiple objects, so in order to ensure that your data is accurate, make sure you always look at the legend if available. 

This is a pie graph. Pie graphs are used to compare the parts to the whole. The bigger the pieces of the pie, the larger the amount is represented as part of the pie.

This is a line graph. Line graphs are generally used to track trends. They can even be used to predict future values.

This is a pictograph. Pictographs are very similar to dot plots. The only difference is that pictures are used to represent objects rather than dots.

This is a tally table. Tally tables are a quick visual display to show the results from collected data. Each tally mark is represented by a vertical line and the 5th line is generally a horizontal line to keep it neat and tidy.

All of these different graphs represent data in different ways.

Data Videos

Practice Questions

Year 7 Big Ideas

Exercise 10C pg. 363 Now Try These: Q. 1-3

 My Maths 8

Exercise 9E pg. 483 Q. 1-7