Your results on the overall patient level contradict results on the subgroup level? There is no need to panic. With a deeper look into the data, one can get to the bottom of this observation. [...]
The mean value of numerical data is without a doubt the most commonly used statistical measure. Anyone who has a basic statistical background knows how to calculate the (arithmetic) mean. However, sometimes the median is used as an alternative to the mean. [...]
In this article we would like to address the question whether it is useful to perform statistical testing in the context of a NIS, as it is often requested by the sponsor, and why, if tests are performed, we should handle their results with caution.