# Australian Bureau of Statistics

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 CensusAtSchool Australia

CaSQ 24A - Writing Instructions to Make a Scatter Plot of Height vs Foot Length

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 How to: Get a Random Sample from CensusAtSchool Go to the CensusAtSchool Random Sampler to download a sample. Reference year: (Select year) Sample size: At least 30 students Select questions: Height Location: Select location Year level: (Select a range of year levels) To protect privacy there is a rule built into the sampler that the requested sample size cannot exceed 10% of the respondents for the parameters entered.

Your classmate Tilly told you that a person’s height is 7 times their foot length. You don’t believe this is true. You really want to prove her wrong. You believe that a relationship can be found between height and foot length by constructing a scatter plot. You decide using CensusAtSchool data will be the best way to decide the matter. You agree that to be fair you should both select different data and make your own scatter plots. To avoid argument you want to make sure that you both follow the same steps in constructing the scatter plots.

In numbered step form write clear instructions for creating a scatter plot. You can use diagrams if necessary. Your instructions can be for hand or for using ICT and must clearly cover the following points in particular:

Selecting the data
• How will the data be selected?
• How many students should be in the sample?

Constructing the scatter plot
• Which variable will be on the horizontal axis and which will be on vertical and how do you know?
• How will you decide the scale for each axis?
• How is each person’s height and foot length shown on the scatter plot?

Finding the relationship
• How will you plot each person’s height and foot length?
• How will you put in the line of best fit?
• How will you use the line of best fit to show the relationship between height and foot length?
• What sort of check should you do to confirm your answer is reasonable?

CaSQ 24B and CaSQ 24C are extensions to this lesson.