Last visit was: 20 Jan 2025, 16:51 It is currently 20 Jan 2025, 16:51
Decision Tracker
My Rewards
New comers' posts
New posts
Unanswered

Close

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

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GRE score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Go to My Error Log Learn more
Close

Request Expert Reply

Confirm Cancel
PREVIOUS TOPIC
NEXT TOPIC

A team of researchers measured each of ten subjects’ reaction time to

Tags :
Find Similar Topics  About  Add a Tag

Show Tags
Hide Tags

User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 30721
Own Kudos [?]: 37109 [7]
Given Kudos: 26145
Send PM
A team of researchers measured each of ten subjects’ reaction time to [#permalink] New post   18 Aug 2021, 05:03
1
Expert Reply
6
Bookmarks
00:00

Question Stats:

22% (01:53) correct 77% (01:47) wrong based on 35 sessions

Hide Show timer Statistics

A team of researchers measured each of ten subjects’ reaction time to a certain stimulus and calculated the mean, median, and standard deviation of the measurements. If none of the reaction times were identical and an eleventh data point were added that was equal to the mean of the initial group of ten, which of these three statistics would change?

(A) The median only
(B) The standard deviation only
(C) The mean and the median
(D) The mean and the standard deviation
(E) The median and the standard deviation


Kudos for the right answer and explanation
Question part of the project GRE Quant/Math Extreme Challenge Daily (2021) Edition
GRE - Math Book
ShowHide Answer
Official Answer
B
User avatar
G
motion2020
Retired Moderator
Joined: 19 Nov 2020
Posts: 326
Own Kudos [?]: 378 [0]
Given Kudos: 64
GRE 1: Q160 V152
Send PM
Re: A team of researchers measured each of ten subjects’ reaction time to [#permalink] New post   19 Aug 2021, 09:26
and when data is skewed, median should change too
:(

Carcass wrote:
A team of researchers measured each of ten subjects’ reaction time to a certain stimulus and calculated the mean, median, and standard deviation of the measurements. If none of the reaction times were identical and an eleventh data point were added that was equal to the mean of the initial group of ten, which of these three statistics would change?

(A) The median only
(B) The standard deviation only
(C) The mean and the median
(D) The mean and the standard deviation
(E) The median and the standard deviation


Kudos for the right answer and explanation
Question part of the project GRE Quant/Math Extreme Challenge Daily (2021) Edition
GRE - Math Book
User avatar
S
aishumurali
Manager
Manager
Joined: 23 May 2021
Posts: 146
Own Kudos [?]: 47 [0]
Given Kudos: 23
Send PM
Re: A team of researchers measured each of ten subjects’ reaction time to [#permalink] New post   19 Aug 2021, 21:48
Hi shouldnt the median also change for this sum?
I considered two sets , and it changes in one and doesn't in another
User avatar
P
Ks1859
Retired Moderator
Joined: 09 Jan 2021
Posts: 576
Own Kudos [?]: 848 [0]
Given Kudos: 194
GRE 1: Q167 V156
GPA: 4
WE:Analyst (Investment Banking)
Send PM
Reviews Badge
A team of researchers measured each of ten subjects’ reaction time to [#permalink] New post   19 Aug 2021, 22:16
Hi There!

The median does not always change.
Consider a set A= a,b,c,d,4,6,e,f,g,h
The median here will be 5

Now, if we add 5 in the above set as the 11th element
a,b,c,d,4,5,6,e,f,g,h- the new median is 5 as well.

Whereas if we consider some other set there is a possibility that the median change as well, but not a compulsion as it is for SD.

Thus B

Carcass don't you think the question should say something like must change? Because would is open for wide interpretation and median can also be included in such case.

Regards
S
User avatar
S
aishumurali
Manager
Manager
Joined: 23 May 2021
Posts: 146
Own Kudos [?]: 47 [0]
Given Kudos: 23
Send PM
Re: A team of researchers measured each of ten subjects’ reaction time to [#permalink] New post   19 Aug 2021, 23:10
Yes , i think the question stem needs to be more precise.
What we know is the sd will surely change irrespective of the data set . The median however depends on the data set , hence there is no sureity :) Thank you!
User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 30721
Own Kudos [?]: 37109 [1]
Given Kudos: 26145
Send PM
Re: A team of researchers measured each of ten subjects’ reaction time to [#permalink] New post   20 Aug 2021, 00:24
1
Expert Reply
Ks1859 wrote:
Hi There!

The median does not always change.
Consider a set A= a,b,c,d,4,6,e,f,g,h
The median here will be 5

Now, if we add 5 in the above set as the 11th element
a,b,c,d,4,5,6,e,f,g,h- the new median is 5 as well.

Whereas if we consider some other set there is a possibility that the median change as well, but not a compulsion as it is for SD.

Thus B

Carcass don't you think the question should say something like must change? Because would is open for wide interpretation and median can also be included in such case.

Regards
S


No

The median is trickier. If none of the original 10 times were identical, the median must have been the average of 2 of those measurements. it's possible that in the original set of 10, the mean and the median were equal; for instance,
that’s the case if the numbers were consecutive. If they were equal, the median stays the same. If the mean and median were not equal, however, it’s possible that the median does change.
avatar
B
test01
Manager
Manager
Joined: 23 Sep 2023
Posts: 65
Own Kudos [?]: 15 [0]
Given Kudos: 59
Send PM
Re: A team of researchers measured each of ten subjects reaction time to [#permalink] New post   17 Oct 2023, 19:37
Carcass wrote:
A team of researchers measured each of ten subjects’ reaction time to a certain stimulus and calculated the mean, median, and standard deviation of the measurements. If none of the reaction times were identical and an eleventh data point were added that was equal to the mean of the initial group of ten, which of these three statistics would change?

(A) The median only
(B) The standard deviation only
(C) The mean and the median
(D) The mean and the standard deviation
(E) The median and the standard deviation



Can someone please explain why would only SD change?

I don't think SD would change, because the 11th data point is equivalent to the mean. I could be wrong, too. Carcass any resources that you might recommend to understand how these stats change with changes in a data set?
User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 30721
Own Kudos [?]: 37109 [0]
Given Kudos: 26145
Send PM
Re: A team of researchers measured each of ten subjects reaction time to [#permalink] New post   17 Oct 2023, 22:53
Expert Reply
Here https://gre.myprepclub.com/forum/gre-me ... tml#p83258 the ONLY notion you need for the GRE about SD

Specifically, memorize the table at the bottom of the guide sir
avatar
B
grehater123456
Intern
Intern
Joined: 19 Oct 2024
Posts: 31
Own Kudos [?]: 15 [0]
Given Kudos: 73
Send PM
Re: A team of researchers measured each of ten subjects reaction time to [#permalink] New post   19 Dec 2024, 21:36
As far as i understand, the question says "would" change, so we should consider the case when median changes right? for example in a non-consecutive set of integers. As opposed to a "must" question where we stick to std only
User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 30721
Own Kudos [?]: 37109 [0]
Given Kudos: 26145
Send PM
Re: A team of researchers measured each of ten subjects reaction time to [#permalink] New post   20 Dec 2024, 02:04
Expert Reply
I agree that this question should be considered like a could be true question.

However, the fact of "would" dows not change dramatically the interpretation of the same
Prep Club for GRE Bot
gmatclubot
Re: A team of researchers measured each of ten subjects reaction time to [#permalink]
20 Dec 2024, 02:04
Moderators:
adewale223
GRE Instructor
89 posts
bronaugust
GRE Forum Moderator
37 posts
BrushMyQuant
Moderator
1131 posts
VibhuAnurag
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Main navigation

Partners

GRE Resources

www.ets.org/gre | About | Terms and Conditions and Privacy Policy | Prep Club for GRE Rules | Contact