It is currently 18 Feb 2018, 23:37

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

There are a lot of products. Is the standard deviation of the prices o

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Expert Post
Math Revolution GMAT Instructor
User avatar
D
Joined: 16 Aug 2015
Posts: 4880
GPA: 3.82
There are a lot of products. Is the standard deviation of the prices o [#permalink]

Show Tags

New post 21 Apr 2017, 00:27
Expert's post
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

39% (01:04) correct 61% (01:06) wrong based on 66 sessions

HideShow timer Statistics

There are a lot of products. Is the standard deviation of the prices of the products less than $60?

1) The median value of their price is $100
2) The range of their price is $110
[Reveal] Spoiler: OA

_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself
See our Youtube demo

Senior Manager
Senior Manager
User avatar
G
Joined: 02 Mar 2017
Posts: 271
Location: India
Concentration: Finance, Marketing
Re: There are a lot of products. Is the standard deviation of the prices o [#permalink]

Show Tags

New post 21 Apr 2017, 19:56
I am Not sure whether i am Right....There a rule suggesting STD Should be approximately equal to One fourth the value of the range...

Here Range is 110 So STD will be less than 60...
statement 1 tells next to nothing..

Hence B
_________________

Kudos-----> If my post was Helpful

1 KUDOS received
Manager
Manager
avatar
P
Joined: 17 May 2015
Posts: 210
CAT Tests
Re: There are a lot of products. Is the standard deviation of the prices o [#permalink]

Show Tags

New post 21 Apr 2017, 22:58
1
This post received
KUDOS
VyshakhR1995 wrote:
I am Not sure whether i am Right....There a rule suggesting STD Should be approximately equal to One fourth the value of the range...

Here Range is 110 So STD will be less than 60...
statement 1 tells next to nothing..

Hence B


Hi VyshakhR1995,

To be precise Standard deviation of any data set will always be less than equal to Range/2.

I'll demonstrate it with a small example.

consider two numbers 6 and 10.

1. Find the mean. (6+10)/2 = 8

2. Take the difference from the mean. 8 - 6 = 2 , 10 - 8 = -2

3. Square the difference. 2^2 = 4, (-2)^2 = 4

4. Take the mean of the squares of the difference from the mean. => (4+ 4)/2 = 4

5. Take the square root of step 4 result. => \(\sqrt{4} = 2\)

Standard deviation = 2

Range = 10 - 6 = 4 .

In this case, SD is equal to Range/2.

But if you insert any other element within this range, then SD will further decrease.

=> Standard deviation <= Range/2

Thanks.
Expert Post
1 KUDOS received
Math Revolution GMAT Instructor
User avatar
D
Joined: 16 Aug 2015
Posts: 4880
GPA: 3.82
Re: There are a lot of products. Is the standard deviation of the prices o [#permalink]

Show Tags

New post 24 Apr 2017, 01:46
1
This post received
KUDOS
Expert's post
==> If you modify the original condition and the question, you get standard deviation(d)≤range/2. Then, from d≤range/2=$110/2=$55<$60, it is always yes and sufficient.

Therefore, the answer is B.
Answer: B
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself
See our Youtube demo

Re: There are a lot of products. Is the standard deviation of the prices o   [#permalink] 24 Apr 2017, 01:46
Display posts from previous: Sort by

There are a lot of products. Is the standard deviation of the prices o

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.