Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Mar 2709:30 AM PDT
-10:30 AM PDT
Preparing for the GMAT? Avoid these 5 major mistakes that can lower your score and hurt your MBA dreams. In this expert panel discussion, 4 top GMAT coaches - GMAT Ninja, Jeff Miller from TTP, Rida Shafiq from eGMAT, and Chris Gentry from Manhattan Prep- Mar 27
10:00 AM PDT
-11:00 AM PDT
What happens after getting an MBA? Is it worth the investment? To find out, I interviewed 10 GMAT Club professionals who have completed their MBAs and built careers in consulting, finance, tech, and entrepreneurship. Their answers might surprise you! 
Mar 2911:30 AM EDT
-12:30 PM EDT
Learn how Keshav, a Chartered Accountant, scored an impressive 705 on GMAT in just 30 days with GMATWhiz's expert guidance. In this video, he shares preparation tips and strategies that worked for him, including the mock, time management, and more.
Mar 3005:30 AM PDT
-07:30 AM PDT
We know Strengthen and Weaken questions account for more than 50% of the CR questions on the GMAT. With CR becoming even more important on GMAT Focus, it's time you strengthen your weaknesses with an approach that improves your solving time and accuracy!
Mar 3011:00 AM IST
-01:00 PM IST
Attend this session to evaluate your current skill level, learn process skills, and solve through tough Arithmetic questions.
Mar 3110:00 AM EDT
-11:59 PM EDT
The Target Test Prep team has recently introduced TTP OnDemand GMAT, a 400-hour live masterclass video course created by Scott Woodbury-Stewart, founder and CEO of Target Test Prep.
Apr 0308:00 PM PDT
-09:00 PM PDT
Full-length FE mock with insightful analytics, weakness diagnosis, and video explanations!
23 May 2018, 18:10
Kudos
Bookmarks
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
35%
(medium)
Question Stats:
60% (01:02) correct
40%
(01:05)
wrong
based on 142
sessions
History
Date
Time
Result
Not Attempted Yet
[GMAT math practice question]
There are 100 employees in a company. Is the standard deviation of their monthly salaries less than $1000?
1) The average of the salaries is $3,000
2) The range of the salaries is $500
There are 100 employees in a company. Is the standard deviation of their monthly salaries less than $1000?
1) The average of the salaries is $3,000
2) The range of the salaries is $500
alldaytestprep
Expert
Tutor
Joined: 08 May 2018
Last visit: 24 Apr 2023
Posts: 98
Given Kudos: 1
Affiliations: All Day Test Prep
Location: United States (IL)
Schools: Booth '20 (A)
GMAT 1: 770 Q51 V49
GRE 1: Q167 V167
GPA: 3.58
Expert reply
23 May 2018, 20:44
Kudos
Bookmarks
There are 100 employees in a company. Is the standard deviation of their monthly salaries less than $1000?
1) The average of the salaries is $3,000
2) The range of the salaries is $500
All you need to know about standard deviation for the GMAT is a conceptual understanding of what it is. Standard deviation is a measure of how far on average the numbers in a set are from the mean.
1) Know nothing about the numbers other than the mean. Need to know something about how spread out they are relative to the mean. ----> Insufficient
---> eliminate A & D
2) This means the most spread out any two numbers in the entire set are is $500. Therefore, on average the remaining numbers are all closer together meaning the standard deviation must be less than $500. If SD is less than $500 it will also be less than $1000 ------> Sufficient.
This might be best illustrated with some examples.
$1(min)........................$501(max) ---------------> the mean lies somewhere in between. there's no way for remaining numbers to be on average $1000 away from the mean since they're all also in-between.
$1,000,000(min)...................................................$10,000,500(max) -------> same as above except using larger salaries. Sames rules apply.
Answer: B
1) The average of the salaries is $3,000
2) The range of the salaries is $500
All you need to know about standard deviation for the GMAT is a conceptual understanding of what it is. Standard deviation is a measure of how far on average the numbers in a set are from the mean.
1) Know nothing about the numbers other than the mean. Need to know something about how spread out they are relative to the mean. ----> Insufficient
---> eliminate A & D
2) This means the most spread out any two numbers in the entire set are is $500. Therefore, on average the remaining numbers are all closer together meaning the standard deviation must be less than $500. If SD is less than $500 it will also be less than $1000 ------> Sufficient.
This might be best illustrated with some examples.
$1(min)........................$501(max) ---------------> the mean lies somewhere in between. there's no way for remaining numbers to be on average $1000 away from the mean since they're all also in-between.
$1,000,000(min)...................................................$10,000,500(max) -------> same as above except using larger salaries. Sames rules apply.
Answer: B
25 May 2018, 02:37
Kudos
Bookmarks
=>
Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.
Suppose d is the standard deviation of the data set and r is the range of the data set. Then d ≤ r. Since we have many variables, E is most likely to be the answer. So, we should consider conditions 1) & 2) together first. After comparing the number of variables and the number of equations, we can save time by considering conditions 1) & 2) together first.
Conditions 1) & 2)
Since d ≤ r, we have d ≤ 500 < 1000.
Both conditions are sufficient, when taken together.
Since this question is a statistics question (one of the key question areas), CMT (Common Mistake Type) 4(A) of the VA (Variable Approach) method tells us that we should also check answers A and B.
Condition 1)
As there is no relationship between standard deviation and average, condition 1) is not sufficient.
Condition 2)
Since d ≤ r, we have d ≤ 500 < 1000.
Condition 2 is sufficient.
Therefore, B is the answer.
Answer: B
Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.
Suppose d is the standard deviation of the data set and r is the range of the data set. Then d ≤ r. Since we have many variables, E is most likely to be the answer. So, we should consider conditions 1) & 2) together first. After comparing the number of variables and the number of equations, we can save time by considering conditions 1) & 2) together first.
Conditions 1) & 2)
Since d ≤ r, we have d ≤ 500 < 1000.
Both conditions are sufficient, when taken together.
Since this question is a statistics question (one of the key question areas), CMT (Common Mistake Type) 4(A) of the VA (Variable Approach) method tells us that we should also check answers A and B.
Condition 1)
As there is no relationship between standard deviation and average, condition 1) is not sufficient.
Condition 2)
Since d ≤ r, we have d ≤ 500 < 1000.
Condition 2 is sufficient.
Therefore, B is the answer.
Answer: B
