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

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
Live EA class + 6 months of EA OnDemand
  • Expert-led weekly online sessions
  • EA Masterclass access between classes
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

130-point score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

If a certain set of GMAT test score has a mean of 550

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 1223
Joined: Sat Feb 15, 2020 2:23 pmFollowed by: 1 member
by BTGModeratorVI » Sun Feb 23, 2020 6:48 am

Timer

00:00

Answers

A

B

C

D

E

Stats

Difficulty—

If a certain set of GMAT test score has a mean of 550 and a standard deviation of 23, and Rob's score is within two standard deviations from the mean, which of the following CANNOT be Rob's score?

A) 402
B) 543
C) 550
D) 583
E) 590

Source: Economist
Answer: A
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |

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

Re: If a certain set of GMAT test score has a mean of 550

by Brent@GMATPrepNow » Wed Feb 26, 2020 7:27 am
BTGModeratorVI wrote: ↑
Sun Feb 23, 2020 6:48 am
 If a certain set of GMAT test score has a mean of 550 and a standard deviation of 23, and Rob's score is within two standard deviations from the mean, which of the following CANNOT be Rob's score?

A) 402
B) 543
C) 550
D) 583
E) 590

Source: Economist
Answer: A
-----ASIDE----------------------
A little extra background on standard deviations above and below the mean

If, for example, a set has a standard deviation of 4, then:
1 standard deviation = 4
2 standard deviations = 8
3 standard deviations = 12
1.5 standard deviations = 6
0.25 standard deviations = 1
etc


So, if the mean of a set is 9, and the standard deviation is 4, then:
2 standard deviations ABOVE the mean = 17 [since 9 + 2(4) = 17]
1.5 standard deviations BELOW the mean = 3 [since 9 - 1.5(4) = 3]
3 standard deviations ABOVE the mean = 21 [since 9 + 3(4) = 21]
etc.
-----------------------------------
Mean = 550
Standard deviation = 23
So, 2 standard deviations BELOW the mean = 550 - (2)(23) = 504
And 2 standard deviations ABOVE the mean = 550 + (2)(23) = 596

GIVEN: Rob's score is within two standard deviations from the mean
So Rob score is BETWEEN 504 and 596

Check the answer choices.....
Answer choice A does NOT fall within this range

Answer: A

Cheers,
Brent
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
GMAT Instructor
Posts: 8177
Joined: Sat Apr 25, 2015 10:56 amFollowed by: 29 members
Location: Los Angeles, CA
Thanked: 43 times

Re: If a certain set of GMAT test score has a mean of 550

by Scott@TargetTestPrep » Fri Feb 28, 2020 8:02 am
BTGModeratorVI wrote: ↑
Sun Feb 23, 2020 6:48 am
 If a certain set of GMAT test score has a mean of 550 and a standard deviation of 23, and Rob's score is within two standard deviations from the mean, which of the following CANNOT be Rob's score?

A) 402
B) 543
C) 550
D) 583
E) 590

Source: Economist
Answer: A
Two standard deviations from the mean is:

550 - 2(23) = 504 and 550 + 2(23) = 596.

We see that Rob’s score can be any number from 504 to 596. So 402 cannot be Rob’s score.

Answer: A

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

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