Originally Posted by
compiforce
I am not a pilot, but I am a Chartered Engineer, Chartered Statistician, a Chartered IT Professional, a European Engineer, and a Fellow of the Royal Statistical Society, with a Doctorate in Operational Research and Mathematical Statistics.
Not all natural distributions are Normal. However, very many are, because of the Central Limit Theorem. In essence, if a physical measurement is the sum of smaller figures, it is very likely to be Normal. That's why heights of people are approximately Normal, IQs are roughly Normal, etc.
It would be very surprising if the performance of pilots differed much from a Normal distribution.
A Normal (or Gaussian) Distribution is entirely described by its mean and variance. So, unless the distribution of performance of pilots is very unusual (such as a Laplace Distribution), the only relevant features of the distribution of pilot performance will be the mean (or average) and the variance (which determines how many are in the "tails" and how long the "tails" are).
Q: If the average applicant scores 100 points on the pilot qualification test, made up of theoretical questions, and a simulator check, you say they should probably normally distributed. Lets say 60 % score between 90 and a 110 points, and the airlines only hire the pilots with over 90 points. With the 20% percent who didn't cut it missing, wouldn't the resulting curve be non-normally distributed? (and seeing hiring rates around 50% at interviews makes me think the skewing would be worse)
Had statistics class in college about 3 decades ago.....