The rule of 5

“We must become more comfortable with probability and uncertainty.” ~ Nate Silver

If you told me that your processing team turned around over a thousand widgets per day and that you just asked five people how long their last widget took to process: 28, 36, 24, 30 and 31 minutes. Now if I say that I predict your median process time is somewhere between 24 and 36 minutes you will probably think that’s a reasonable guess based on the few examples. However, if I then said I was over 93% sure of my prediction, you might think I was being rather over confident. Lets look at the maths behind why I can be so sure with so few data points.

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