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Old 09-17-2012, 05:55 AM
vtrajan@vtrajan.net vtrajan@vtrajan.net is offline
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Default Question 7-9: all overwhelms one, should we use weights

Dear Prof:
I questions 7-9, in one vs all, the number of all instances is about 9 times the number of one, so it overwhelms the one. The results are skewed in one direction. Should we use different weights to compensate for this? Give weights for each class proportional to 1/number of instances?

As it stands now, I am not sure the answers are that meaningful.

But I would guess that the answers that the system accepts assumes that there is no weighting of the classes, each instance has the same weight.

Rajan
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Old 09-17-2012, 07:41 AM
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yaser yaser is offline
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Default Re: Question 7-9: all overwhelms one, should we use weights

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Originally Posted by vtrajan@vtrajan.net View Post
Dear Prof:
I questions 7-9, in one vs all, the number of all instances is about 9 times the number of one, so it overwhelms the one. The results are skewed in one direction. Should we use different weights to compensate for this? Give weights for each class proportional to 1/number of instances?
In general some weighting can be used to balance different classes. This is not done in this problem for the sake of simplicity.
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