GRE Question of the day – 9/10/16

b – a = 10                                                                     

c – b = 4              

                    Quantity A                                                                                   Quantity B

Standard deviation of a, b ,and c                           Standard deviation of 2, 12, and 16

  1. Quantity A is greater than B
  2. Quantity B is greater than A
  3. Both the Quantities are Equal
  4. The relationship cannot be determined with the given information.
Expert Asked on October 9, 2016 in GRE Quant.
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3 Answer(s)

3)Both quantities are equal

Default Answered on October 10, 2016.
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Is there any other method to find the deviation apart from the conventional method?

Default Answered on October 10, 2016.
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Yes the answer is C(Both are equal).

You mean the conventional method here is the formulaic approach ?

In that case, no need of formula and all…

All you need to do is find the spread of the elements in the set, Greater the spread, greater the standard deviation will be.

So all you need to do is find the difference from the average to each and every element, greater the difference then greater the standard deviation.

Or else just remember that, if the number of elements of two sets are same,

then compare the Standard deviation with range.

remember that range is proportional to standard deviation. greater the range , greater the standard deviation.

Here in this question, both the sets have same spread. So standard will be the same.

a = x

b = x+10

c = x+14

Where the spread is same as the Quantity B.

So the answer is C.

 

Expert Answered on October 12, 2016.
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