Standard Deviation Problem

Expert replies

yvonne0923: Senior | Next Rank: 100 Posts; Posts: 96; Joined: Mon Mar 07, 2011 8:43 pmFollowed by: 1 member; Thanked: 1 times

by yvonne0923 » Fri May 06, 2011 12:00 pm

Is the standard deviation of Set A greater than the standard deviation of Set B?
(1) the range of A is greater than the range of B
(2) The sets have the same number of terms

_____________________________________________________________________________________________________
[spoiler]O.A: E[/spoiler]
My answer is B, since(1) definitely does not work, but (2)the sets have the same numbers of terms. Does it mean both sets have 7 terms(for example) or exactly same numbers?

Thanks,

[/spoiler]

Like this post

Source: Beat The GMAT — Data Sufficiency | Fri May 06, 2011 12:00 pm

force5: Legendary Member; Posts: 582; Joined: Tue Mar 08, 2011 12:48 amFollowed by: 6 members; Thanked: 61 times; GMAT Score:740

by force5 » Fri May 06, 2011 12:20 pm

i didnt like this question. what is the source?

well if i consider what you have written then i would answer E.

statement 1 talks about range which is insufficient to tell us about standard deviation.

statement 2 talks about same number of terms. it can have 2 terms each or 5 terms each. but we dont know the distribution. hence insufficient.

combining still insufficient

This doesnt make a good question. there has to be something missing in this question.

Like this post

Arcane66: Senior | Next Rank: 100 Posts; Posts: 81; Joined: Sat Aug 08, 2009 1:16 pm; Thanked: 2 times

by Arcane66 » Fri May 06, 2011 6:45 pm

I got E too. I actually looked up standard deviation again and the basic formula for it. I know you can't tell from #1 or #2 alone. #1 doesn't tell you anything because all the terms in between the highest and lowest numbers could be disproportionately large or small. #2 by itself doesn't mean anything because we don't know the values. With both you still don't know because of the fact that you could have values skewed high or low.

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

563 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (563 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review