Null Hypothesis Formulation: Purpose and Errors

Prof. Mary Ferrill gives a clear illustration of how to analyze an Non-Inferiority (NI) trial.

To begin with, we have to learn the differences between superiority and non-inferiority.

In addition, there are five stepwise approaches to analyze NI clinical trials. We should formulate the null hypothesis, assess the NI margin, compare the ITT and PP results, translate the CI results graphically, and finally summarize the clinical relevance of the results.

When formulating NI trials, we should notice NI margin or threshold, which is also called Delta and listed by Greek letters.

NOTE: The null hypothesis for a non-inferiority study says that there is a difference, and the null statement for NI studies is opposite of what is formulated for a superiority trial.

Therefore, the purpose in a NI trial is to reject the null hypothesis. If you are confused with this idea, please watch the example in this video or leave your question below.

Ultimately, we should know how to distinguish type I and type II errors from the final table in this video.