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Is this actually a lot more complicated than I think

Neil3030 · 2018-01-23 06:43:27

Suppose I have a group of integers: [-6 4 -5 -9] I want to find the number y, so that the average of the new array: [-6 4 -5 -9 y] is as close to zero as possible.... ?

23-01-2018 6:43am

#1

Neil3030

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Suppose I have a group of integers:

[-6 4 -5 -9]

I want to find the number y, so that the average of the new array:

[-6 4 -5 -9 y]

is as close to zero as possible.... ?

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#2 23-01-2018 6:49am

whomitconcerns

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Y is 11 or 21 gives you an average of -1/1

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#3 23-01-2018 6:55am

Neil3030

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Thanks, so y can actually be a Real number if needed. Sorry, should have specified.

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#4 23-01-2018 7:11am

Neil3030

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OK so think I got it...

You insert -ab, where a is the number of elements in the original array, and b is the original mean

So in the above:
mean of [-6 4 -5 -9 16] = 0

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#5 23-01-2018 7:16am

Lu Tze

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Neil3030 wrote: »

Thanks, so y can actually be a Real number if needed. Sorry, should have specified.

In that case:
-6+4-5-9+y=0
=> y=16

Or am I missing something? Average is sum divided by count, and if the average equals zero, then dividing by count is irrelevant I.e. also zero? Hence sum = zero?

0