From your comment history you appear to have some background in statistics, but what you&#x27;re written here is curiously missing the fundamentals.  It&#x27;s not exactly clear what you&#x27;re arguing, but I am definitely curious because I must be missing it!<p>To answer your last question directly: nobody argues that there are zero differences between groups in an experiment, but rather that the central limit theorem applies, which is a statement about the distribution of means in particular circumstances.  <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Central_limit_theorem" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Central_limit_theorem</a>