Second: a population is the group from which a sample is drawn. Since the normal distribution being discussed was not that of a sample, but that of the total population, we are clearly talking about populations. Your assumption is based on your ignorance of what was being discussed, as you have admitted ( I put your admission of ignorance in bold for you so that you are aware of that admission).
Third: He was obviously not referring to a study, which is abundantly clear by virtue of his answer to the very question "What study are you referring to?". See posts 739 and 740 for evidence of this. It's important to not be ignorant of what's being discussed before injecting yourself into a discussion.
Now who's never taken a stats class?This is what I first saw, which (at least in statistics) doesn't make much sense. Especially because 5% on each side of a normal curve is almost always the maximum any statistician would use in determining if something occurred by chance (normally) or due to something else.
What does my statement that you quoted have to do with determining chance?