Bias significance test

Hi @abatalla and @nmilders

I have just pushed changes to the Bias() function to the development branch dev-sigBias

If absolute is set to FALSE and alpha is numeric, Welch's test is used to calculate whether the two samples (exp and obs) have equal means.

Maybe other people (@acarreri @rfernand @cdelgado ...) have different approaches to compute the significance or feedback for this development. If that's the case, please let me know.

Here there is an example of the result compared to the original function:

Kind regards,

Núria