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Signature length 2

Data collection

Use measurements of lengths collected in the activity Signature Length 1 or negotiate rules for collecting data (e.g. write both first and last name only, use pencil or pen, measure in mm, dominant hand, non-dominant hand).

Data representation

Create stacked dot plots for each group and a back-to-back stem-and-leaf plot.

If considering dominant and non-dominant hands, create a new variable (difference = non-dominant – dominant) to explore differences.

Create a stacked dot plot or stem-and-leaf plot for the difference variable. How is this useful?


Compare shapes of distributions in the plots.

Compare means, medians, modes, clumps, humps, gaps and outliers.

Create and compare box-and-whisker plots for the two groups (if appropriate for year level).

Degree of certainty

Would the data look the same if two other samples were used to collect data?

Drawing an informal inference

Write a report answering the question. Include a statement about your level of confidence in the inference made and discuss the uncertainty evident in the results.

Curriculum links

Year 9: Identify everyday questions and issues involving at least one numerical and at least one categorical variable, and collect data directly from secondary sources (ACMSP228)

Year 10: Construct and interpret box plots and use them to compare data sets