to use the power of mumsnet to help me with maths?

[kolacubes]

I am trying to do a weighted average, and was wondering if any of you brainy bods could tell me how to do it.

if i have the following information

10 40%
5 30%
3 20%
1 10%

what would the weighted average be?
what would be the weighted figure for
10
5
3
1
be?

Thank you.

4
1.5
0.6
0.1

ave = 6.2

Thanks please could you tell me how to do it.

Weighted average = (1040) + (530) + (320) + (110) / 100
= 6.2

You need to add up all the (values * the weighting) and divide by the total of the weightings.

Thank you both for your assistance.

Awful mathematical statement.
Stick some brackets round the whole of the sum ...

Surely you divide by the number of instances (in this case 19 = 10+5+3+1). So the weighted average = 620/19 = 32.63%. Which sounds about right, seeing as there are 10 instances of 40% and only 1 of 10%.

Strawbezza has found the weighted average of the percentages whereas I assume it's the first column you are averaging and the second column is the weights?

Yes its the first column is the average, and the second column for the weights.