Weekly Math Quest - Dec10th, 2006

[gmat_enthus]

Q. Is the standard deviation of A=0?
1) The minimum value of the elements in set A is 5
2) The set A has 20 elements

The answer will be posted along with the solution on Sunday, Dec 17th, 2006. Till then you can disucss your solutions here.

reference: Scorechase GMAT forum

[800guy]

Q. Is the standard deviation of A=0?
1) The minimum value of the elements in set A is 5
2) The set A has 20 elements

The answer will be posted along with the solution on Sunday, Dec 17th, 2006. Till then you can disucss your solutions here.

reference: Scorechase GMAT forum

this looks like E to me

1) is not sufficient by itself--they could be all 5 or one value of 5 with other values in the set

2) is not sufficient by itself because it says nothing about the values of the elements

together, 1) and 2) are not sufficient because it could imply: 20 elements with all values of 5, or 20 elements with at least one value of 5.

E

[gmat_enthus]

Even I got E.

[gmat_enthus]

Guys, the siteadmin on Scorechasejust posted that OA is not E. for this weeks GMAT Math Quest. They are not going to reveal the OA till 10th.

Any other guesses?

Could it be A, since minimum value is 5 means there is one more value which is not 5 so SD cannot be 0?

So A sound good?

[800guy]

i suppose a...i'm confused

[chaitu_suvanam]

So if a set has only element 5 does that mean minimum function has no meaning on that set.

I feel it is a ambiguous question.... Can some one tell me where I can get GMAT definition of Min function.[/spoiler]

[cyrwr1]

I'm going with E. Feedback and explanations greatly appreciated as I am not sure what minimum value in a set means. does it mean the smallest is that value?

[Night reader]

Q. Is the standard deviation of A=0?
1) The minimum value of the elements in set A is 5
2) The set A has 20 elements

The answer will be posted along with the solution on Sunday, Dec 17th, 2006. Till then you can disucss your solutions here.

reference: Scorechase GMAT forum

question is S(standard deviation)=0 ?
(1) n-number of elements in set A, n>=1 (set exists with at least one value!), x_i(1...n) is element in set A, Sigma(sum)x_i=1...n >=5 Not Sufficient, as set A may contain 5 2-s and S=0 and may contain 2 2-s and 3 3-s S is not equal to 0;
(2) n=20 Not Sufficient, as we don't know the value of elements
Combined st(1&2) set A {x_1, x_2, x_3... x_20} Sigma(A)>=5 OR (x_1+x_2+x_3+... x_20)>=5; if Sigma(A)<5
x(mean/average)<5/20 OR x(average)<1/4, Not Sufficient, as depending on the values in set A, S can OR can not be equal to 0.

Per the question stimuli and conditions given, I think it's answer E.