Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 30 Jun 2010
Posts: 1

10 students took a chemistry exam that was graded on a scale [#permalink]
Show Tags
30 Jun 2010, 20:00
Question Stats:
74% (01:12) correct 26% (01:16) wrong based on 488 sessions
HideShow timer Statistics
10 students took a chemistry exam that was graded on a scale of 0 to 100. Five of the students were in Dr. Adams’ class and the other five students were in Dr. Brown’s class. Is the median score for Dr. Adams’ students greater than the median score for Dr. Brown’s students? (1) The range of scores for students in Dr. Adams’ class was 40 to 80, while the range of scores for students in Dr. Brown’s class was 50 to 90. (2) If the students are paired in study teams such that each student from Dr. Adams’ class has a partner from Dr. Brown’s class, there is a way to pair the 10 students such that the higher scorer in each pair is one of Dr. Brown’s students.
Official Answer and Stats are available only to registered users. Register/ Login.




Manhattan Prep Instructor
Joined: 29 Apr 2010
Posts: 125

Re: 10 students took a chemistry exam that was graded on a scale [#permalink]
Show Tags
30 Jun 2010, 22:39
This is a Yes/No Data Sufficiency question that never requires you to identify the specific values of the medians just to answer a question about their relative values. Remember that the medianas opposed to the meanonly depends on the value of the middle term (or 2 middle terms if you have an even number of elements in your list, but each class has an odd number of students here) when all the terms are listed in order. For example: For the set {1, 1, 1, 2, 100}  median = 1 For the set {1, 1, 1, 1, 1}  median = 1 For the set {1000, 100, 1, 20, 99999} yup, median still equals 1. Statement 1 tells you about the RANGE of scores in class A(dams). Range only involves the endpoints of the list. The middle term could be ANY number within that range. For example: {40, 40, 40, 40, 80}  median = 40 {40, 50, 60, 70, 80}  median = 60 {40, 80, 80, 80, 80}  median = 80 Likewise, a range of 50 to 90 could give you any of the following for class B(rown): {50, 50, 50, 50, 90}  median = 50 {50, 51, 62, 84, 90}  median = 62 {50, 90, 90, 90, 90}  median = 90 In order for the statement to be sufficient to answer the question, you would have to be say whether all possible medians for all possible set As were always greater than (or always less than) the medians for all possible set Bs. Since we have a "sometimes it might be, sometimes it might not" situation, this statement is INSUFFICIENT. Statement 2, however, tells you that it's possible to pair up each student so that each score in set A corresponds to a HIGHER score in set B. So if you listed out the elements in set A in ascending order: { p, q, r, s, t} then set B must contain: {#bigger than p, #bigger than q, #bigger than r, #bigger than s, #bigger than t} What is the median of set A? The middle term r. What's the median of set B? Something bigger than r. Even though I have NO IDEA what those numbers are, if I put them in order I know that the middle term of set B will have to be greater than the middle term of set A. SUFFICIENT. Hope this helps.
_________________
JP Park  Manhattan GMAT Instructor  Los Angeles
Manhattan GMAT Discount  Manhattan GMAT Reviews




Senior Manager
Joined: 29 Jan 2011
Posts: 315

DS  MGMAT 10 students took a chemistry exam [#permalink]
Show Tags
Updated on: 20 Jun 2011, 22:27
Please explain in detail...
10 students took a chemistry exam that was graded on a scale of 0 to 100. Five of the students were in Dr. Adams’ class and the other five students were in Dr. Brown’s class. Is the median score for Dr. Adams’ students greater than the median score for Dr. Brown’s students?
(1) The range of scores for students in Dr. Adams’ class was 40 to 80, while the range of scores for students in Dr. Brown’s class was 50 to 90.
(2) If the students are paired in study teams such that each student from Dr. Adams’ class has a partner from Dr. Brown’s class, there is a way to pair the 10 students such that the higher scorer in each pair is one of Dr. Brown’s students.
Originally posted by siddhans on 20 Jun 2011, 06:27.
Last edited by siddhans on 20 Jun 2011, 22:27, edited 1 time in total.



Senior Manager
Joined: 30 Aug 2009
Posts: 276
Location: India
Concentration: General Management

Re: MGMAT DS [#permalink]
Show Tags
20 Jun 2011, 06:40
siddhans wrote: Please explain in detail...
10 students took a chemistry exam that was graded on a scale of 0 to 100. Five of the students were in Dr. Adams’ class and the other five students were in Dr. Brown’s class. Is the median score for Dr. Adams’ students greater than the median score for Dr. Brown’s students?
(1) The range of scores for students in Dr. Adams’ class was 40 to 80, while the range of scores for students in Dr. Brown’s class was 50 to 90.
(2) If the students are paired in study teams such that each student from Dr. Adams’ class has a partner from Dr. Brown’s class, there is a way to pair the 10 students such that the higher scorer in each pair is one of Dr. Brown’s students. Statement1  Given Dr. Adams’ class Range is 4080 Dr. Brown’s class Range is 50 to 90 Case 1 Scores in Dr. Adams’ class can be 40,50,75,80,80 so median is 75 Scores in Dr. Brown’s class can be 50,60,70,80,90 so median is 70 and the answer is Yes Case 2 Scores in Dr. Adams’ class can be 40,50,75,80,80 so median is 75 Scores in Dr. Brown’s class can be 50,60,80,85,90 so median is 80 and the answer is No Hence Insuff Statement 2 What can be concluded that all students of Dr Brown's Class have scores higher than all the students of Dr Adam's Class. So Median of Dr Adam' Class is less than Median of Dr Brown's Class. So we get a definite answer as No. Hence suff Ans B



Senior Manager
Joined: 29 Jan 2011
Posts: 315

Re: MGMAT DS [#permalink]
Show Tags
20 Jun 2011, 08:35
kp1811 wrote: siddhans wrote: Please explain in detail...
10 students took a chemistry exam that was graded on a scale of 0 to 100. Five of the students were in Dr. Adams’ class and the other five students were in Dr. Brown’s class. Is the median score for Dr. Adams’ students greater than the median score for Dr. Brown’s students?
(1) The range of scores for students in Dr. Adams’ class was 40 to 80, while the range of scores for students in Dr. Brown’s class was 50 to 90.
(2) If the students are paired in study teams such that each student from Dr. Adams’ class has a partner from Dr. Brown’s class, there is a way to pair the 10 students such that the higher scorer in each pair is one of Dr. Brown’s students. Statement1  Given Dr. Adams’ class Range is 4080 Dr. Brown’s class Range is 50 to 90 Case 1 Scores in Dr. Adams’ class can be 40,50,75,80,80 so median is 75 Scores in Dr. Brown’s class can be 50,60,70,80,90 so median is 70 and the answer is Yes Case 2 Scores in Dr. Adams’ class can be 40,50,75,80,80 so median is 75 Scores in Dr. Brown’s class can be 50,60,80,85,90 so median is 80 and the answer is No Hence Insuff Statement 2 What can be concluded that all students of Dr Brown's Class have scores higher than all the students of Dr Adam's Class. So Median of Dr Adam' Class is less than Median of Dr Brown's Class. So we get a definite answer as No. Hence suff Ans B Kudos



Manager
Joined: 22 Feb 2016
Posts: 98
Location: India
Concentration: Economics, Healthcare
GMAT 1: 690 Q42 V47 GMAT 2: 710 Q47 V39
GPA: 3.57

Re: 10 students took a chemistry exam that was graded on a scale [#permalink]
Show Tags
15 Nov 2016, 10:10
parker wrote: This is a Yes/No Data Sufficiency question that never requires you to identify the specific values of the medians just to answer a question about their relative values.
Remember that the medianas opposed to the meanonly depends on the value of the middle term (or 2 middle terms if you have an even number of elements in your list, but each class has an odd number of students here) when all the terms are listed in order. For example:
For the set {1, 1, 1, 2, 100}  median = 1 For the set {1, 1, 1, 1, 1}  median = 1 For the set {1000, 100, 1, 20, 99999} yup, median still equals 1.
Statement 1 tells you about the RANGE of scores in class A(dams). Range only involves the endpoints of the list. The middle term could be ANY number within that range. For example: {40, 40, 40, 40, 80}  median = 40 {40, 50, 60, 70, 80}  median = 60 {40, 80, 80, 80, 80}  median = 80
Likewise, a range of 50 to 90 could give you any of the following for class B(rown): {50, 50, 50, 50, 90}  median = 50 {50, 51, 62, 84, 90}  median = 62 {50, 90, 90, 90, 90}  median = 90
In order for the statement to be sufficient to answer the question, you would have to be say whether all possible medians for all possible set As were always greater than (or always less than) the medians for all possible set Bs. Since we have a "sometimes it might be, sometimes it might not" situation, this statement is INSUFFICIENT.
Statement 2, however, tells you that it's possible to pair up each student so that each score in set A corresponds to a HIGHER score in set B.
So if you listed out the elements in set A in ascending order: { p, q, r, s, t} then set B must contain: {#bigger than p, #bigger than q, #bigger than r, #bigger than s, #bigger than t}
What is the median of set A? The middle term r. What's the median of set B? Something bigger than r. Even though I have NO IDEA what those numbers are, if I put them in order I know that the middle term of set B will have to be greater than the middle term of set A. SUFFICIENT.
Hope this helps. I remember totally freaking out when this question appeared in my Mock and I thought whoa I am so bad and I will never get it correct. but careful examination of of the question stem and playing with variables helped me get the correct answer. Now looking at your explanation boosted me further as I had moved in the exact way. YAY! Thanks these little victories means a lot in this painful journey.



Director
Joined: 12 Nov 2016
Posts: 774
Location: United States
GRE 1: 315 Q157 V158
GPA: 2.66

Re: 10 students took a chemistry exam that was graded on a scale [#permalink]
Show Tags
10 Sep 2017, 23:39
ace001 wrote: 10 students took a chemistry exam that was graded on a scale of 0 to 100. Five of the students were in Dr. Adams’ class and the other five students were in Dr. Brown’s class. Is the median score for Dr. Adams’ students greater than the median score for Dr. Brown’s students?
(1) The range of scores for students in Dr. Adams’ class was 40 to 80, while the range of scores for students in Dr. Brown’s class was 50 to 90.
(2) If the students are paired in study teams such that each student from Dr. Adams’ class has a partner from Dr. Brown’s class, there is a way to pair the 10 students such that the higher scorer in each pair is one of Dr. Brown’s students. Nice question All statement 2 is basically saying is that for every student in Dr. Adams class, a student in Dr. Browns class scored higher so if both classes have the same number of people then the median will naturally be higher even if you minimize the potential scores of Dr. Browns class Dr A. [10,20,30,40,50] Dr B [20,30,40,50,60] The median is clearly higher B



Senior Manager
Joined: 15 Jan 2017
Posts: 362

Re: 10 students took a chemistry exam that was graded on a scale [#permalink]
Show Tags
13 Sep 2017, 00:39
Pretty much a dead giveway with B for A) we don't know the exact scores so Median can be higher for either Dr A or Dr B B) says each time the score for Dr B is higher > therefore Me is higher




Re: 10 students took a chemistry exam that was graded on a scale
[#permalink]
13 Sep 2017, 00:39






