As I See It: You can believe so if you wish

If you measure a characteristic of a biological population, it usually fits a bell-shaped curve; the majority will fit near the middle. As we take a measure further from the middle there will be more deviation from the median characteristic. At the extremes we find the radicals and fanatics, often described as the “x percenters.” This works whether we are measuring height, wealth or opinion. A good design typically fits the 5th to 95th percentile. That way 90% of the users will usually be satisfied. Those over 6 feet, 7 inches will have to duck sometimes. Those less than 4 feet, 10 inches will need a step stool often. That is why shoes and clothes are made in many sizes.