Let's assume we have two data samples. One of them has an additional parameter. This parameter does not initially exist in that data sample. But after being added, we can see one of other attributes of the sample (e.g. performance percentage) has increased considerably. In the other sample, the performance percentage is not increased. While the other sample does not have this parameter, how can we make sure if the change in performance percent in the first sample is directly related with the increase in that specific parameter?
Thanks
