Statistics · JSS 2
Mean (average)
Share the total equally: the everyday 'average'.
- x̄ = Σxn
What the letters mean
- x̄
- the mean ('x bar')
- Σx
- the sum of all the values
- n
- how many values there are
Worked example
Find the mean of 4, 7, 9, 10 and 15.
Step 1: Add the values
4 + 7 + 9 + 10 + 15 = 45
Step 2: Divide by how many
45 ÷ 5 = 9
Final answer: 9
See it
Play with this picture from the Mean, Median and Mode lesson.
Tap a value to change it. Put them in order to find the middle:
Value 12
Mean
2
10 ÷ 5
Median
2
the middle one
Mode
2
most common
Range
5
5 − 0