Chebyshev's Theorem

Standard deviation, mean, variance, z-scores, t-tests, etc.
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taytay822
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Chebyshev's Theorem

Postby taytay822 » Thu Oct 01, 2009 12:41 am

The mean income of a group of sample observations is $500; the standard deviation is $40. According to Chebyshev's theorem, at least what percent of the incomes will lie between $400 and $600?

I tried the formula 1-1/k2 and I am not coming out with the right answer... please help

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stapel_eliz
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Postby stapel_eliz » Thu Oct 01, 2009 12:43 pm

Please show your steps, so we can try to help you find any error(s). Also, please provide the book's answer. (It might be wrong!)

Thank you! :wink:

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taytay822
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Re: Chebyshev's Theorem

Postby taytay822 » Tue Oct 06, 2009 1:18 am

I am doing an online assignment and whenever I typed in the answer it told me I had it incorrect. I received some help from a classmate, but I still don't know how they got the k or the std. dev

_
x ± k*s

1-1/k2

1-1/(2.5)2

1-1/6.25

=.84 or 84%

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stapel_eliz
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Postby stapel_eliz » Tue Oct 06, 2009 12:38 pm

taytay822 wrote:I still don't know how they got the k or the std. dev

You were given the standard deviation: 40.

The interval they gave you was one hundred to either side of the mean. How many standard deviations is this? (Hint: Divide 100 by 40.)

The number of standard deviations is the value of k. :wink:


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