Theory
When there are several measurements, you often use the average, because individual measurements can differ a little.
Add all the measurements together and then divide by the number of measurements.
Write the answer with a suitable unit.
- Add up the measurementsAdd up all the values from the list systematically.
You get a sum of values by adding all the numbers together.
Work systematically from left to right, or first make useful groups.
At the end, check that each number from the list has been counted exactly once.
- Count the number of measurementsCount how many separate values are in the row.
A value is one separate number in a row of data.
The number of values is therefore not the sum of the numbers, but how many numbers are in the row.
Count the values one by one and stop when you have gone through the whole row.
- Divide by the number of measurementsDivide the sum by the number of values.
An average divides the total sum equally among all values.
If you already know the sum and the number of values, you only need to divide.
Use: average = sum : number of values.
- Write down the averageWrite the answer with a suitable unit.
- Add up the measurements12,1, 12,3 and 12,2 together gives 36,6.
- Count the number of measurementsThere are 3 values in 12,1, 12,3 and 12,2.
- Divide by the number of measurements36,6 ÷ 3 = 12,2.
- Write down the averageThe average is 12,2 m.