ans is 6 & 6. Why?
if you add 6 & 6 to the list the, avg does not change and adding the two #'s will actually make the std dev smaller because you have more #'s that are less from the mean(std dev).
BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course
Redeem
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
certain list of 100 data...PT
Source: Beat The GMAT — Problem Solving |
gmattester,
Take an eg of the set {2 4 6}
The mean will be 4.
The standard deviation can be found as [ (-2)^2 + 0^2 + (2)^2 /3 ]^1/2 (hope u get this step)
standard deviation = ( 8/3 ) ^ 1/2
When u add 4 and 4 to the set mentioned above ..
The standard deviation can be found as [ (-2)^2 + 0^2 + 0^2 + 0^2+ (2)^2 /5 ]^1/2
If u notice the denominator increases but numerator does not when 4 and 4 are added to {2 4 6}
Take an eg of the set {2 4 6}
The mean will be 4.
The standard deviation can be found as [ (-2)^2 + 0^2 + (2)^2 /3 ]^1/2 (hope u get this step)
standard deviation = ( 8/3 ) ^ 1/2
When u add 4 and 4 to the set mentioned above ..
The standard deviation can be found as [ (-2)^2 + 0^2 + 0^2 + 0^2+ (2)^2 /5 ]^1/2
If u notice the denominator increases but numerator does not when 4 and 4 are added to {2 4 6}
