1. Mean Average often means the ‘mean’
Mean = total of the numbers divided by how many numbers.
Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6
Add up the numbers:
= 40
Divide by how many numbers:
40 ÷ 10 = 4
The class mean shoe size is 4

2. Mode Mode is the most common number Put the numbers in order
Choose the number that appears the most frequently.
Sometimes there may be more than one mode.
Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6
Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6
The class modal shoe size is 5.

3. Median Median is the middle value Put the numbers in order
Choose the number in the middle of the list.
If there are 2 numbers in the middle then it is halfway between them.
Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6
Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6
The class median shoe size is 4.5

4. Lower Quartile Referred to as LQ or Q1.
The median of the lower half of the numbers.
Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6
Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6

5. Upper Quartile Referred to as UQ or Q32
The median of the upper or larger half of the numbers.
Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6
Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6

6. Range Range is how far from biggest to smallest.
Put the numbers in order
Take the smallest number from the largest.
Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6
Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6
Subtract smallest from largest: 6 – 1 = 5
Range: 5