Question

The daily rainfall for each day of a week in a certain city is given in millimetres. Find the average rainfall during the week. 9,11,8,20,10,16,12

Answer 1

Hint: In the above question we have to find the average rainfall during the week. So, for this we will use the formula for finding average which is mentioned below.
Average\[ = \]\[\dfrac{{sum{\text{ }}of{\text{ }}all{\text{ }}observation}}{{total{\text{ }}number{\text{ }}of{\text{ }}observation}}\] use this formula in order to get the required answer.

Complete step-by-step answer:
We have given rainfall during the week as 9,11,8,20,10,16,12 millimetres.
To calculate average rainfall during the week use the formula for finding the average.
i.e. Average\[ = \]\[\dfrac{{sum{\text{ }}of{\text{ }}all{\text{ }}observation}}{{total{\text{ }}number{\text{ }}of{\text{ }}observation}}\]
Here, observations are 9mm,11mm,8mm,20mm,10mm,16mm,12mm
And number of observation \[ = \]7
Putting the values in the formula we get,
Average \[ = (\dfrac{{9 + 11 + 8 + 20 + 10 + 16 + 12}}{7})mm\]
\[ \Rightarrow \] Average \[ = \dfrac{{86}}{7}\]mm
\[ \Rightarrow \] Average\[ = 12.28\]mm
Hence, the average rainfall during the week is 12.28 millimetres.

Note: An average is a single number taken as representative of a list of numbers. Often average refers to arithmetic mean, the sum of the numbers divided by how many numbers are being averaged.