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Topic: [ap-stat] random variables
Replies: 21   Last Post: Dec 2, 2005 12:58 PM

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Bill Beumer

Posts: 72
Registered: 12/6/04
[ap-stat] random variables
Posted: Nov 29, 2005 1:40 PM
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Why is it that when adding a random variable to itself (X+X), the
variance of the new random variable Y=X+X is just the variance of X
added to itself, while the variance of Z=2X is 4 times the variance of
X? Why are these 2 variances different?

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