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The standard deviation of

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The standard deviation of

by Max@Math Revolution » Tue Apr 07, 2020 3:23 am

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[GMAT math practice question]

The standard deviation of x1, x2, …, x5 is 2√2. What is the standard deviation of √2x1, √2x2, …, √2x5?

A. 0
B. 1
C. 2
D. 3
E. 4
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Re: The standard deviation of

by Max@Math Revolution » Thu Apr 09, 2020 6:05 pm
=>

Remind the property that S(aX+b) = |a|S(X) where S(X) is the standard deviation of set X and X is a data set.

S( \(\sqrt{2}\) x1, \(\sqrt{2}\) x2, …, \(\sqrt{2}\) x5) = \(\sqrt{2}\) S(x1,x2,x3,x4,x5) = \(\sqrt{2}\) *(2 \(\sqrt{2}\) ) = 4.

Therefore, E is the answer.
Answer: E
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