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Math Forum » Discussions » Courses » ap-stat

Topic: Acorn book question
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egilcreast

Posts: 6
Registered: 12/6/04
Acorn book question
Posted: Apr 12, 1997 10:53 AM
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Sorry, made a typing error in my previous message. If two populations have
means 424 and 478 and each had standard deviations 100, why isn't the standard
deviation of the sum equal to sqrt(100^2 + 100^2)? Means are additive and I
thought variances were additive too. The Acorn book says there's not enough
information. Philip Mallinson

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