Box plots (also called box-and-whisker plots) are introduced in Year 8 and revisited through senior statistics. This lesson plan walks students through the five-number summary, builds plots from real data, and uses them to compare distributions across groups.
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These short tasks surface what students already know about median and range from earlier year levels, and expose the most common misconceptions: confusing the median with the mean, mis-ordering the data before finding quartiles, and forgetting to scale the number line.
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Real-life application tasks use data students recognise: class test scores, daily rainfall, train delays, or AFL and NBA player statistics. Students build parallel box plots to compare two groups and answer a guiding question, such as which class was more consistent or which dataset has a wider spread.
Differentiation is built in. Enabling prompts step students through quartile calculations with a partly completed five-number summary; extending prompts ask students to compare three or more box plots, justify whether a value is a genuine outlier, and explain what a box plot hides that a histogram shows.
These short tasks surface what students already know about median and range from earlier year levels, and expose the most common misconceptions: confusing the median with the mean, mis-ordering the data before finding quartiles, and forgetting to scale the number line.
Choosing familiar contexts gives the statistics a reason to exist. Students stop asking what the IQR is for and start using it as evidence in a comparison, which is exactly the reasoning the senior curriculum builds on.
Differentiation is built in. Enabling prompts step students through quartile calculations with a partly completed five-number summary; extending prompts ask students to compare three or more box plots, justify whether a value is a genuine outlier, and explain what a box plot hides that a histogram shows.
- You in approximately four minutes
Introduction to Box Plots
Constructing and Interpreting Box Plots
Comparing Data Using Box Plots
Students meet box plots from Year 8 as a way to summarise a data set on a single number line. The lesson plan opens with the five-number summary (minimum, lower quartile, median, upper quartile, maximum), then shows how those five points map directly to the whiskers, box edges and median line.
Students order a data set, calculate quartiles, and draw a box plot to scale on a number line. They then read the plot in the other direction: describing the spread using range and interquartile range, identifying outliers with the 1.5 x IQR rule, and commenting on skewness from where the median sits inside the box.
By Year 9 and 10, students use parallel box plots to compare two or more groups. They justify claims with measures of centre and spread rather than eyeballing the plot, and explain when a box plot is more useful than a histogram or dot plot. In senior statistics, this work feeds directly into describing distributions and discussing variation.
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