Re: Can you predict randomness within a certain percentage?

Hi! Brad,

That is an excellent question. Indeed your intuition is right too. Let's 
make it even simpler. Say we only have two kinds of balls, red and blue, 
five in each color. When you mix them up and pour them into 2 groups 
(randomly), each group will have 5 balls. Our intuition tells us  that it 
is very unlikely that one of the groups will end up to have 5 red balls. We 
actually expect that each group would have 50% red and 50% blue. 

Of course we would never have 2.5 (that's 50% of 5) red balls in a group of 
five (as we are only pouring them instead of cutting them up). What we are 
saying here is that if we do this process over and over again, say, 500 
times, that is, we mix the red and blue balls up and pour them into 2 
groups of 5 for 500 times. Each time we calculate the percentage of red 
balls (or blue balls) in a group. At the end, we will have 500 percentages 
of red balls. Most of them will be either 40% (2/5) or 60% (3/5) and the 
average of these 500 percentages will be very close to 50%. 

Hope this helps. 

[note added by MadSci Admin:  For details on making the
relevant calculations please refer to your statistics
book(s)!]