BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

women 25-59 years of age

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 amFollowed by: 80 members
Location: India
Thanked: 267 times
GMAT Score:760
by sanju09 » Sun Nov 24, 2013 4:40 am
If 96 percent of women 25-59 years of age at Country Q weigh between 97.5 lbs and 155 lbs, and this data is normally distributed, then which of the following is the best approximation for the mean and standard deviation of their weights in pounds, respectively?
A. 100 and 30
B. 110 and 25
C. 120, and 20
D. 125 and 15
E. 140, and 10


Made Up!
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 490
Joined: Thu Jul 04, 2013 7:30 amFollowed by: 5 members
Location: Chennai, India
Thanked: 83 times

by Uva@90 » Sun Nov 24, 2013 5:42 am
sanju09 wrote:If 96 percent of women 25-59 years of age at Country Q weigh between 97.5 lbs and 155 lbs, and this data is normally distributed, then which of the following is the best approximation for the mean and standard deviation of their weights in pounds, respectively?
A. 100 and 30
B. 110 and 25
C. 120, and 20
D. 125 and 15
E. 140, and 10


Made Up!
Sanju09,

Is Answer D ?

Regards,
Uva.
Known is a drop Unknown is an Ocean
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Sun Nov 24, 2013 7:46 am
sanju09 wrote:If 96 percent of women 25-59 years of age at Country Q weigh between 97.5 lbs and 155 lbs, and this data is normally distributed, then which of the following is the best approximation for the mean and standard deviation of their weights in pounds, respectively?
A. 100 and 30
B. 110 and 25
C. 120, and 20
D. 125 and 15
E. 140, and 10

Made Up!
This question is out of scope, since the GMAT does not test one's knowledge of Normal Distributions.

Cheers,
Brent

PS: Normal Distributions were recently been added to the GRE curriculum but not the GMAT curriculum .
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pmFollowed by: 511 members
Location: Palo Alto, CA
Thanked: 2867 times
GMAT Score:800

by [email protected] » Sun Nov 24, 2013 5:23 pm
Hi All,

Brent is absolutely correct in that the GMAT won't test one's knowledge of Standard Deviation in this way. In addition, the way the answers are written, calculating the Stand Deviation wouldn't even be necessary.

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 amFollowed by: 80 members
Location: India
Thanked: 267 times
GMAT Score:760

by sanju09 » Tue Nov 26, 2013 12:53 am
Tough GMAT problems expect us know the answers of any of the following questions:

"¢ What is Standard Deviation?
"¢ How is Standard Deviation related with Variance and Range of a distribution?
"¢ What is the significance of Standard Deviation?
"¢ What is Normal Distribution, and what is it to do with the Standard Deviation and the Bell Curve?
"¢ What is a Bell Curve? What is the approximated break up percentages of the Bell Curve?
"¢ What do we mean by 1 or 2 Standard Deviation(s) below or above the Mean? Etc...

Yes, GMAT never make us calculate the Standard Deviation the real way, but at the same time it may test us over the understanding, applying, and approximating the Standard Deviation from the necessary info provided.

96 percent is almost 100 percent. If this data is normally distributed, then 97.5 lbs and 155 lbs are the real extremes, whose average is the approximated mean.

� Mean = (97.5 + 155)/2, approximately equal to 125.

If 97.5 lbs and 155 lbs are the real extremes, then the Range of the distribution is the difference of the extremes.

� Range = 155 - 97.5, or approximately equal to 57; and in the absence of real data, if only the Range of the data is known, one-fourth of the Range is an rough approximation for the Standard Deviation. Hence, the Standard Deviation of the presented data is roughly around ¼ (57), 15 is the best value to pick.

[spoiler]Where do we find 125 and 15 together?[/spoiler]
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Tue Nov 26, 2013 7:48 am
sanju09 wrote:Tough GMAT problems expect us know the answers of any of the following questions:

"¢ What is Standard Deviation?
"¢ How is Standard Deviation related with Variance and Range of a distribution?
"¢ What is the significance of Standard Deviation?
"¢ What is Normal Distribution, and what is it to do with the Standard Deviation and the Bell Curve?
"¢ What is a Bell Curve? What is the approximated break up percentages of the Bell Curve?
"¢ What do we mean by 1 or 2 Standard Deviation(s) below or above the Mean? Etc...
I agree with most of these, but I respectfully disagree with the two in blue
The terms "normal distribution" and "bell curve" do not appear anywhere in the Official Guide to GMAT Review (OG13).

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 22
Joined: Sat Mar 06, 2010 12:13 pm
Location: Secret

by Gmat Bond » Tue Nov 26, 2013 7:59 am
Uva@90 wrote:
sanju09 wrote:If 96 percent of women 25-59 years of age at Country Q weigh between 97.5 lbs and 155 lbs, and this data is normally distributed, then which of the following is the best approximation for the mean and standard deviation of their weights in pounds, respectively?
A. 100 and 30
B. 110 and 25
C. 120, and 20
D. 125 and 15
E. 140, and 10


Made Up!
Sanju09,

Is Answer D ?

Regards,
Uva.
Have you lost it like him? The GMAT never asks questions about Normal Distribution!
The name is Bond, GMAT BOND !!
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 447
Joined: Fri Nov 08, 2013 7:25 amFollowed by: 1 member
Thanked: 25 times

by Mathsbuddy » Fri Nov 29, 2013 10:05 am
Surely the mean would just be symmetrically between the 97.5 and 155 poles (with 2% either side of that again)? 126.25

Answer D?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 amFollowed by: 80 members
Location: India
Thanked: 267 times
GMAT Score:760

by sanju09 » Sat Nov 30, 2013 12:00 am
Correction

if only the Range of the data is known, one-fourth of the Range is a rough approximation for the Standard Deviation.

Can anybody tell what I really corrected?
A. He
B. Will
C. Get
D. An
E. Apple

[spoiler]PS: Brent is absolutely correct that the OG never used the term Normal Distribution. Fault is mine, because when I describe SD in a GMAT session, I prefer to provide them the mystery from all weird corners. I request the esteemed moderators to move this thread to some GRE bin and wash hands.[/spoiler]
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1