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arithmatic mean

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arithmatic mean

by vertigo05 » Sat Apr 25, 2009 9:53 am
For a certain set of n numbers, when n>1, is the average(arithmetic mean) equal to the median?

(1) If the n numbers in the set are listed in increasing order, the difference between any pair of successive numbers is 2.
(2) The average of the n numbers in the set is 2(n-1).
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by scoobydooby » Sat Apr 25, 2009 10:08 am
average=median for set of equally spaced integers.

1) difference between any pair of successive numbers is 2=> a set of equally spaced integers with common difference 2.
so average =median
sufficient


2) average of n numbers is 2(n-1)
=> sum of n numbers is 2n(n-1)
cant say if numbers are equally spaced
not sufficient

hence, A
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by vertigo05 » Sun Apr 26, 2009 8:25 am
hey scoobydooby,
Thanx. OA is "A".
Median is the middle no. when the numbers in the given set are arranged in increasing order. When the set contains even number of numbers, the median is the avg of the two middle numbers. This case is not mentioned in option no.1.
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