On the behalf of Psychologists and similar researcher´s fauna
1. - NHST was not designed to ascertain that the Null Hypothesis is true or untrue. Instead to traditional Logic they are concerned with two chosen Hypothesis Null H0 and Alternative Ha (Neyman-Pearson algorithm) the criterion being to opt by the more likely after setting a large probability (0.95/0.99) not to reject H0. 2. - By the above later sentence when it happens to fail to reject H0 i.e. the value of the test not falling at the Rejection Interval, we are not aware to state that the Null Hypothesis is true. Instead we should say that we not found sufficient evidence that the Null is unlike. 3. - To reject H0 (statistical significance) is a consequence that the difference of the observed quantity and that concerned the Null cannot be ascribed to random fluctuations. It does not inform how large the difference is, and much less the practical/economic worth. 3.a - An adequately chosen quantity a0 can be added to null in order that, in case of significance, this quantity is assured to be really present.