“The Parity of Zero, the Primality of Two, and Other Mysteries”, 2017-07-19 (; backlinks; similar):
From time to time, I try to speak or write about mathematics for general (non-mathematical) audiences. If you’ve done this, you know it’s pretty hard—in large part because it’s hard to know what people know, despite my best attempts to find out.
Enter Google Surveys. For a pretty reasonable fee, it turns out anyone can run a survey through Google; the respondents are randomly selected and reweighted by demographics (age, gender, location). So I decided to find out: What percentage of Americans over the age of 18 know what a prime number is [out of the list 2/9/13/33/31/57]? What about an even number [0/8/17/99/257/774]? I also tried to design the questions so they tested a bit more than basic knowledge; for example, I wanted to know whether the respondents knew that zero is even (a surprisingly controversial topic)…Each survey received about 250 responses from randomly selected Americans over the age of 18. (And cost me a well-spent $30.44$252017.)
…The percentages indicate how many survey-takers thought the number in question was even. So about 75.7% of people think 8 is even (not bad!) but 774 is much harder. I don’t know what was going on with the 0.8% of people who thought that 17 was even, but maybe this is an example of the Lizardman constant.
Even numbers: In particular, more than half of the survey-takers were able to get 5 or 6 answers correct. Not too shabby! To get a perfect score, one had to identify zero as even, which only 24% of the respondents were able to do, so I think this is a pretty good result. Interestingly, about 2⁄3 of the people who correctly identified zero as even got perfect scores. The median number of correct answers was 5⁄6; the mean was about 4.5.
Prime numbers: Identifying primes was evidently much harder. The median number of correct answers was 3⁄6 (no better than chance), and the mean was about 3.6.
…I was a bit surprised how few respondents knew that 0 is even. Parity is a concept which actually comes up in daily life—for example, when one wants to know which side of the street a given address is on, or in certain regulatory questions. I was also a bit surprised that it was so difficult to identify 2 as a prime.