GRE Prep 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.
Set A {300,400,500,700,900} Set B {100,200,300,500,900}
[#permalink]
05 Dec 2018, 09:32
05 Dec 2018, 09:32
2
4
Bookmarks
00:00
Question Stats:
87% (00:51) correct
12% (00:36) wrong based on 160 sessions
Hide Show timer Statistics
Set A {300,400,500,700,900}
Set B {100,200,300,500,900}
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given
Set B {100,200,300,500,900}
Quantity A |
Quantity B |
Standard deviation of Set A |
Standard deviation of Set B |
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given
Re: Set A {300,400,500,700,900} Set B {100,200,300,500,900}
[#permalink]
05 Dec 2018, 10:22
05 Dec 2018, 10:22
1
Expert Reply
1
Bookmarks
Arun1992 wrote:
Set A {300,400,500,700,900}
Set B {100,200,300,500,900}
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given
Set B {100,200,300,500,900}
Quantity A |
Quantity B |
Standard deviation of Set A |
Standard deviation of Set B |
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given
The standard deviation is dependent on the spread of the elements.
Although it is highly unlikely that we will be required to calculate a standard deviation, but we should be able to relate the spread of elements in sets.
Set A {300,400,500,700,900}... Mean = \(\frac{2800}{5}=580\)
Set B {100,200,300,500,900}....Mean = \(\frac{2000}{5}=400\)
we can see that set B has more spread around its mean, thus B>A
B
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: Set A {300,400,500,700,900} Set B {100,200,300,500,900}
[#permalink]
06 Dec 2018, 08:12
06 Dec 2018, 08:12
3
Arun1992 wrote:
Set A {300,400,500,700,900}
Set B {100,200,300,500,900}
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given
Set B {100,200,300,500,900}
Quantity A |
Quantity B |
Standard deviation of Set A |
Standard deviation of Set B |
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given
For many standard deviation questions on the GRE, we can often just "eyeball" the numbers in each set to get a feel for which set has the greatest dispersion (aka deviation).
If we do so, we can see that the numbers in Set B are more dispersed, which means Set B has the greater standard deviation
Answer: B
---------------------------------
Alternatively, we can apply the informal definition of standard deviation (covered in the video below) to conclude that Set B has the greater standard deviation.
