📊 Part 1: Key Concepts

Mean (Average)

Definition: Add all numbers together, then divide by how many numbers there are.

Formula: Mean = Sum of all values ÷ Number of values

Example: For 2, 4, 6, 8: Mean = (2+4+6+8) ÷ 4 = 20 ÷ 4 = 5

Median (Middle Value)

Definition: The middle number when all numbers are arranged in order.

Steps: 1) Put numbers in order 2) Find the middle number

Example: For 1, 3, 5, 7, 9: Median = 5 (middle number)

Even numbers: For 2, 4, 6, 8: Median = (4+6) ÷ 2 = 5

Mode (Most Common)

Definition: The number that appears most often in a set of data.

Example: For 1, 2, 3, 3, 4: Mode = 3 (appears twice)

Note: Some data sets have no mode or multiple modes.

Range (Spread)

Definition: The difference between the highest and lowest values.

Formula: Range = Highest value - Lowest value

Example: For 2, 5, 8, 12: Range = 12 - 2 = 10

🎯 Part 2: Practice Problems

Calculate:

Mean: _________________ cm

Median: _________________ cm

Mode: _________________ cm

Range: _________________ cm

Show your working to find each measure:

💡 Part 3: Quick Reference

a) The _____________ is found by adding all values and dividing by the number of values.

b) The _____________ is the middle value when data is arranged in order.

c) The _____________ is the most frequently occurring value.

d) The _____________ shows how spread out the data is.

Finding the most popular shoe size: _________________

Finding a typical test score (with some very low scores): _________________

Finding how spread out the data is: _________________

Finding the overall average performance: _________________

Remember:

• Always arrange data in order first for median and range

• Mean uses all values in the calculation

• Mode might not exist or there might be multiple modes

• Range tells us about the spread, not the centre