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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!

### 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.