CNN Poll Showing Biden In The Lead Sampled Statistically Insignificant Number Of Voters Under 50

[dsc]

12. I didn't watch the entire video

but I think I get the gist of their argument. I teach math for a living and have taught AP stats (though admittedly not in about a decade). There are two issues they are bringing up. One is that there aren't enough young people polled relative to the percent they are of the voting population (they polled only septegenarions) and two is that the young people they polled are too small a sample to be representative. To evaluate the first we would need to know the relative numbers who vote and how many were polled. Clearly they polled fewer young people but we don't know how many fewer they polled nor do we know how many fewer of them vote. The reason they put the N/A in those columns is that they couldn't find small enough confidence intervals given the size of those samples. That doesn't mean that the number of people in that sample wasn't the proper number given the percent who vote.

As to the representativeness of the sample, they might have a point or they might not. We do know that the confidence interval would have been large (though not how large) and that due to that they didn't produce one nor list percentages. That is all we know. It should be noted though that provided the percent of young people in the sample was correct as to the percent of the voting population, then even if this were an unrepresentative sample it wouldn't have had a huge effect (since it was small). In short, the first issue is the bigger problem and they do nothing at all to tell us if it exists or doesn't.