seminal analyses

Doing some recreational data analysis. Above is a graph using data from the NLSY79. In 1984, a random sample of Americans aged 20-27 were asked "When in the menstrual cycle is pregnancy most likely to occur?" The answer categories given were "Right after the period," "During period," "Right before the period," "2 weeks after period begins," and "Anytime during the month." The pink and blue lines above represent the percentage correct answers for women and men, with the x-axis representing deciles of scores on the Armed Forces Qualifying Test.

Um, if you don't know, the correct answer is "2 weeks after period begins."

Update: Scintillating as the first graph may be, this second one is better.



This is the percentage of people not giving the correct answer who answered "don't know," rather than guessing incorrectly at one of the alternatives provided. The results above indicate that for men, the smarter you are (as far as test scores go), the less likely you are to indicate that you don't know what you don't know.