Signature length 1

Set the question:
How long is a typical year X student’s signature?

Data collection

Negotiate rules for collecting data:

  • write either/or both first and last name
  • use a pencil or ballpoint pen,
  • dominant or non-dominant hand.

Measure in mm (discuss the need for accuracy).

Discuss how many measurements would be needed to make a reliable prediction.

Representing data

List and order data for the class.

Create a stacked dot plot for class data.

Summarising data

Discuss information shown in the class data plot.

For the stacked dot plot discuss the mean, median, mode, range, clumps, humps, gaps and outliers.

Create a box-and-whisker plot (if appropriate for year level). How does it help describe the data set?

Degree of certainty

What aspects of the investigation affect the variation in the data and the uncertainty of the conclusion?

Would the data look the same if another class collected the data (perhaps in another country)?

Drawing an informal inference

Write a report, including all of the assumptions made and limitations experienced, to explain how the class arrived at the length of the typical year X student’s signature.

Curriculum links

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

Year 9: Compare data displays using mean, median and range to describe and interpret numerical data sets in terms of location (centre) and spread

Year 8: Explore the practicalities and implications of obtaining data through sampling using a variety of investigative processes