You may have heard, “Always do subgroup analysis, but never believe them.” Don't believe this.
The over-reliance on p-values can lead to misinterpretation of data and a $150 million bet on a subgroup with scant evidence.
How do we know when an observed effect is real or spurious?
Some people say, "A p-value=0.05 is not very much evidence against the null hypothesis." Well then, how much evidence is it?
pr(B|A) ≠ 1 – pr(A|B). Why do we act like it ?!