Stabilization of the variance

In many types of analytical equipment, the error is a fixed percentage of the maximum instrument reading, which results in a variance proportional to y, i.e. a y,. This gives an uneven variance distribution that calls for using a weight factor, for example 1 /yf, or a logarithm  

2 Placing greater/less weight on certain experimental parts 

For the case using weight factors, the weighted sum of square errors, WSSE, can be expressed as follows  

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