On Thu, 10 May 2007 11:48:03 +0100 Andy McKenzie wrote :
Perfection must be wonderful. Experienced drivers may well make numerous
assumptions. A very common one is that they are 'better than average'. About
80% of drivers think they are better than average, so even if the 50% of
drivers who are better than average correctly self identify, 30% of drivers
must be deluded.

Not if average = mean. If 90 drivers each have one accident every ten years and
10 drivers each have an accident every year, the average driver has 1.9
accidents every ten years but 90% have a better than average accident rate.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk