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 →

Standard deviation and % ?

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |
Legendary Member
Posts: 940
Joined: Tue Aug 26, 2008 3:22 amFollowed by: 1 member
Thanked: 55 times

Re: Standard deviation and % ?

by iamcste » Sun May 17, 2009 10:03 am
California4jx wrote:can anyone provide explanation - OA: A
A


when data points are scaled or multipled by a constant, sdeviation is scaled or multipled by the same constant

here, after removing 30% of water from each tank, each tank has 0.7 of water hence standard deviation would be multipled by 0.7

since we know value of sd before removal of water, we can calculate sd after removal of water =0.7*10= 7 gallons

in stmt 2, we dont know the individual data points to calculate sd post removal of water
Last edited by iamcste on Sun May 17, 2009 10:05 am, edited 1 time in total.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pmFollowed by: 11 members
Thanked: 331 times

by cramya » Sun May 17, 2009 10:04 am
https://www.beatthegmat.com/gmat-prep-qu ... t2120.html
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 227
Joined: Thu Aug 14, 2008 10:43 amFollowed by: 1 member
Thanked: 7 times
GMAT Score:650

by California4jx » Sun May 17, 2009 11:46 am
Thanks !! - very good link.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 227
Joined: Thu Aug 14, 2008 10:43 amFollowed by: 1 member
Thanked: 7 times
GMAT Score:650

Re: Standard deviation and % ?

by California4jx » Sun May 17, 2009 11:47 am
iamcste wrote:
California4jx wrote:can anyone provide explanation - OA: A
A


when data points are scaled or multipled by a constant, sdeviation is scaled or multipled by the same constant

here, after removing 30% of water from each tank, each tank has 0.7 of water hence standard deviation would be multipled by 0.7

since we know value of sd before removal of water, we can calculate sd after removal of water =0.7*10= 7 gallons

in stmt 2, we dont know the individual data points to calculate sd post removal of water
Thanks.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1