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Chebyshev's Theorem

Posted: Thu Oct 01, 2009 12:41 am
by taytay822
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

Posted: Thu Oct 01, 2009 12:43 pm
by stapel_eliz
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:

Re: Chebyshev's Theorem

Posted: Tue Oct 06, 2009 1:18 am
by taytay822
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%

Posted: Tue Oct 06, 2009 12:38 pm
by stapel_eliz
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: