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Weighted Mean help please (stats)

Ok so my problem is with part b.

What does this mean how would I go about answering this question.
Thanks !
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Original post by Olive123
Ok so my problem is with part b.

What does this mean how would I go about answering this question.
Thanks !


The weights will be in the ratio of 23 : 8 : 14 : 11 : ... : 23.

The sum of the weights must equal 1, so you need to scale them appropriately.


E.g.

If your data was 3,4,5, they would need to be weighted in the ratio 3 : 4 : 5.

Since 3+4+5=12, we need to multiply the ratios by 1/12 to get the weightings, viz. 3/12, 4/12, 5/12.
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Olive123
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Original post by ghostwalker
The weights will be in the ratio of 23 : 8 : 14 : 11 : ... : 23.

The sum of the weights must equal 1, so you need to scale them appropriately.


E.g.

If your data was 3,4,5, they would need to be weighted in the ratio 3 : 4 : 5.

Since 3+4+5=12, we need to multiply the ratios by 1/12 to get the weightings, viz. 3/12, 4/12, 5/12.


Well I have just done the sum of (1/206*23) up to the end of the observations and I got 1 . This is wrong I have no idea what im doing :frown:
Original post by Olive123
Well I have just done the sum of (1/206*23) up to the end of the observations and I got 1 . This is wrong I have no idea what im doing :frown:


So, the sum of the weights is 206, and you will need to scale the weights by that factor.

So, for b), the weighting of 23, for example, will be 23/206, as it's proportional to the observation.

The weighted mean is the sum of, the product of the observation times the weight.

So the contribution from the first item will be 23×2320623\times\dfrac{23}{206}, etc.
(edited 10 years ago)

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