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ethame
ethame is offline
#10
Mar1-09, 06:42 PM
P: 2
you have to do as above but then go one step further...to get that 24...

First create a line as below to help you visual the standard deviations...

x-3s-------x-2s-------x-s-------x----------x+s--------x+2s------x+3s
.05--------1.14------2.23-------3.32------4.41--------5.5--------6.59

Chebystev's Theorem states that 3/4 of data lies between x-2s and x+2s
and 8/9 lies between x-3s and x+3s....

Add the data given in the original problem to see how many standard deviations you are within so then you can use the properties of the theorem just mentioned or use the equation: 1- (1/k^2)

According to your question: between 1.14 and 5.5 are 2 standard deviations (x-2s, x+2s)
therefore. We just said above that the theroem states that for this deviation 3/4 of data lies here. But if you want to double check you can use the equaiton:

1-(1/2^2) = 3/4 of the data is within 1.14min and 5.5min

NOW: 3/4 * 32 (number of values) = 24 !