Lesson Plan

• Calculate the mean of a data set using raw values and frequency tables.
• Determine the median for both odd‑ and even‑sized data sets.
• Identify the mode(s) and distinguish unimodal, bimodal, and multimodal distributions.
• Interpret and compare the three measures to describe the shape of a data set.
• Recognise common errors when computing measures of central tendency.

• Projector or interactive whiteboard
• Printed worksheet with frequency tables
• Scientific calculators (one per student)
• Whiteboard and markers
• Rulers for drawing histograms (optional)

Begin with a quick question: “How many books do you think the average student reads each month?” Connect this to students’ prior experience with averages from earlier maths work. Explain that today they will learn three specific ways to summarise data – mean, median and mode – and will be able to choose the most appropriate measure for any data set.

1. Do‑now (5'): Students write down the average number of books they read last month and share with a partner.
2. Mini‑lecture (10'): Teacher defines mean, median, mode, shows formulas and works a simple example on the board.
3. Guided practice (15'): Whole class calculates mean, median and mode for the provided frequency table (books read data), using both raw and frequency methods.
4. Group activity (10'): Small groups create a histogram of the data, discuss which measure best describes the distribution and note any skew.
5. Check for understanding (5'): Exit ticket – “State which measure (mean, median or mode) best represents the data and justify your choice.”

Recap the definitions and calculations of the three measures, highlighting how each gives different insight into the data set. Collect exit tickets to gauge understanding, and assign homework: students must collect a small data set of their own (e.g., minutes spent on homework) and compute the mean, median and mode, then write a brief interpretation.