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I was trying to reduce the skewness of data using boxcox transformation. But was facing an error:
ValueError: Data must be positive.
I figured out why it was throwing an error, my data ranged from .0 to 1 so I added one and it worked.
Although is it the right way to deal with it?
Boxcox you need to tune the lambda parameter, in order to transform the data to normal one (and than its implicitly non-skewed) however, I would suggest to rather use log transform, its faster.
Just look for the smallest non zero entry in your data, let this be e.g. x, then add x/2 to this smallest values and compute the boxcox. Adding a small value i.e epsilon, doesn't affect that much to our data, otherwise adding 1 to all value is also good strategy, you can check which one gives you better results. Here is a link for more info : https://discuss.analyticsvidhya.com/t/methods-to-deal-with-zero-values-while-performing-log-transformation-of-variable/2431/3
