Gmatprep 2

Can someone help in this one?? Will appreciate.

Standard deviation measures how far the terms of a set are spread out. Specifically, it measure how far away they are from the mean.

In this question, we know that the mean is 6 and that the set has a postive standard deviation, although we have no clue what the SD actually is.

We're asked what pair of numbers will definitely result in a lower SD for the set. Since we don't know what the SD is, the only way to guarantee a lower SD is to pick numbers that equal the mean (since numbers directly on the mean are 0 SDs away): choose (e) 6 and 6

Thanks again Stuart!! really appreciate your explanations. I have never seen a question like that before. What does a postive standard deviation mean? a negative SD will be -x above or below the mean?

nadontheway wrote:Thanks again Stuart!! really appreciate your explanations. I have never seen a question like that before. What does a postive standard deviation mean? a negative SD will be -x above or below the mean?

Standard deviation is a measure of distance, so there's no such thing as negative standard deviation.

"Positive SD" just means that the SD does not equal 0; in other words, that not all of the numbers are the same.

I see!! many thanks. I really do appreciate your explanations.

this question isnt really that hard once you boil down the question to its elements.. My problem with questions like this is I know the math tested and how to answer them. I am having trouble taking the words and making it into math in front of me so I can answer it. any words of wisdom?