I am trying to analyse some data using the coefficient of variation (stdev/mean), but I have two problems:
- the data is not 100% positive and:
- the mean is very close to zero (and as Wikipedia says: "When the mean value is near zero, the coefficient of variation is sensitive to change in the standard deviation, limiting its usefulness")
Therefore the coefficient of variation looses it meaning.
So I have thought of adding a constant to each value of my data so to make all values positive and get the mean further away from zero.
Is this a good approach? Would the coefficient be meaningful then? If so, can someone post a proof for this?
- I need it in order to compare the dispersions of more series of data, not to analyse the dispersion of one particular series (in this case probably it wouldn't be meaningful)
I really need to use this coefficient because I need to compare more sets of data and I can't compare their standard deviations since it is an absolute value.
Thanks,
M
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