Researchers collected and studied emails sent by staff at three campus

Question

Researchers collected and studied emails sent by staff at three campuses of an Australian university. The table shows the exact percentages of the sampled emails from each campus that were sent to each of six destinations: the three campuses themselves, two other branch campuses, and locations external to the campuses. The percentages in a column may add to more than 100% because some emails were sent to more than one destination. Emails from Emails to Campus 1 Campus 2 Campus 3 Campus 1 37.4% 31.9% 48% Campus 2 39% 44.9% 24% Campus 3 13% 7% 20% Campus 4 6.5% 2.3% 4% Campus 5 0% 2.3% 0% External 6.5% 11.65% 4% For each of the questions below, select Yes if the question can be answered correctly based on the information provided. Otherwise, select No . ID: 700223 https://gmatclub.com/forum/download/file.php?id=81554 GMAT-Club-Forum-hxz74h7u.png

chetan2u · Accepted Answer

The main point that one has to keep in mind is that you do not what is the number of emails each campus sent or for that matter not even the relative numbers of all three.

1. Were more of the emails sent to Campus 1 than to Campus 2?
Campus 1 and Campus 2 sent more mails to campus 1 than to Campus 2. But Campus 3 sent more mails to Campus 2.
So we cannot find the relative mails received by campus 1 and campus 2.
Say Campus 3 sent 90% of the mails and remaining 10% were sent by Campus 1 and 2…YES
But say Campus 3 sent just 1% of the mails and remaining 99% were sent by Campus 1 and 2…NO

2. Were more of the emails sent to Campus 3 than to Campus 4?
In each of the set of mails sent by Campus 1, 2 and 3, Campus 3 had a higher %. So surely YES in all cases whatever be the numerical value of the mails sent by each.

3. What percentage of the emails to Campus 5 were sent from Campus 2?
Since Campus 5 receives mails only from 2, the answer is 100%
Answer YES.

NO, YES, YES

Iwillget770 , I hope it helps. 
 VishalDamarla , the problem in you answer is that you are not considering the numerical values, which could be anything for each.

columb2025 · Answer

I marked NO for this statement as it isnt mentioned in the question anywhere that only emails form these 3 campuses are recieved by campus 5, what if campus 4/ external were to send mails to campus5. In that case we do not know how much percent of the whole recieved is campus 2 mails. Am i mising something? TIA

anikpait17 · Answer

How are we concluding one without actual numbers of email sent by each of the campuses? % could mean higher percentage of a smaller number versus smaller percentage of a higher number. Hence, how are we concluding "Yes" for the second instance?

chetan2u · Answer

anikpait17

Campus 3 gets a higher percentage of mails in each category. So whatever be the number of mails in each category less or more relative to each other, campus 3 would get more mails than campus 4.

What you have written is the exact reason why statement 1 is No. since campus 1 as compared to campus 2 has more % in two categories and less % in third category. Since we don’t know the exact number we cannot say yes.

Vinit800HBS · Answer

You must look at the percentages and make a logical conclusion for this one.

For Emails sent  FROM CAMPUS 1  to   Campus 3 (13%)   and   Campus 4 (6.5%)  , we can conclude that more emails were sent from Campus 1 to   Campus 3   than from Campus 1 to   Campus 4  . The actual number of emails will depend on the total emails sent from Campus 1 but this does not change the fact that  more emails  were sent to   Campus 3  .

For Emails sent  FROM CAMPUS 2  to   Campus 3 (7%)   and   Campus 4 (2.3%)  , we can conclude that more emails were sent from Campus 2 to   Campus 3   than from Campus 2 to   Campus 4  . The actual number of emails will depend on the total emails sent from Campus 2 but this does not change the fact that  more emails  were sent to   Campus 3  .

For Emails sent  FROM CAMPUS 3  to   Campus 3 (20%)   and   Campus 4 (4%)  , we can conclude that more emails were sent from Campus 3 to   Campus 3   than from Campus 3 to   Campus 4  . The actual number of emails will depend on the total emails sent from Campus 3 but this does not change the fact that  more emails  were sent to   Campus 3.

egmat · Answer

Hi  columb2025 ,
Thank you for bringing up your concern regarding the interpretation of the data about emails sent to Campus 5. Let’s clarify this together!

Observe that the   study mentioned here focuses exclusively on emails sent by staff at three specific campuses of an Australian university.   This implies that the researchers only looked at emails originating from Campus 1, Campus 2, and Campus 3. Other sources, like Campus 4 or external sources, were not included in this particular study.

Therefore, when the table shows that 0% of emails from Campus 1 and Campus 3, and 2.3% of emails from Campus 2 were sent to Campus 5, it means just that – out of all the emails received by Campus 5, none from campus 1 and campus 3 and  ALL  were sent from Campus 2  in this study.  Since the study does not include data from any sources other than these three campuses, this percentage is accurate and complete within the scope of the data collected.

Let me know if this helps address your doubt.  If you have any follow-up questions, do not hesitate to ask. 
Happy Learning!
Regards

abolo · Answer

Hi!

I initially solved this question correctly but right before submitting it I noticed that the stem says that the table was made from a  sample  of emails, whereas the questions are about the emails in general. Also, the question does not include any of those typical statements such as "Assume the sample is representative of the population".

Therefore, I decided that it was a trick question and that no statement is inferable, because the sample might not be representative of all emails. I guess I was too extreme on this assumption...

I would normally make no such reasoning, but I tried this question shortly after getting the following problem wrong  https://gmatclub.com/forum/how-many-people-in-town-x-read-neither-the-world-newspaper-nor-the-glo-305934.html  (in this problem, I thought about the possibility of a third newspaper but discarded it because I thought I was going too far, thus getting it wrong)

I think my mind was caught up on the idea that all of "hard" DI questions are going to have some sort of "gotcha". Once in a while a feel this way, and I dont know if I should just solve the problem straight forward or if there is some sort of trick. Do you have any tips on how to approach this issue?  KarishmaB    GMATNinja   GMATCoachBen   chetan2u

I would appreciate some guidance! Thank you!

callingTardis · Answer

I have confusion regarding the scope of the data.  chetan2u   KarishmaB   MartyMurray  @DmitryFarber 
 The table contains only sampled emails, so we don’t have complete visibility into which campuses are sending emails. Apart from C1, C2, and C3, we don’t know the distribution of emails from other campuses.

for Q3, what if there were 10 other campuses sending mails to campus 5 ?  The table contains only sampled emails.

for Q2, what if there were 10 other campuses sending mails to C3 and C4 and there the percentages were higher for C4 rather than C3 ?  The table contains only sampled emails.

KarishmaB · Answer

The scope of the study is defined. 
 "Researchers collected and studied emails sent by staff at three campuses of an Australian university." Our study includes mails sent my campuses 1, 2 and 3 only. Any mails sent by any other campus is not a part of our study. It is not a part of our depicted numbers. 
Questions ask about "... more of  the  emails..." so they are asking about only those emails that we are considering i.e. emails sent by campuses 1, 2 and 3 only.

denny12233 · Answer

I think this kind of confusion has really no value, I do not see what GMAC is trying to get from this kind of question. In real business world, we would just ask more specified question to avoid any confusion.

ShubhangiGoel · Answer

Hi karishma b

Can you please explain why is no the correct answer for first question?

KarishmaB · Answer

Were more of the emails sent to Campus 1 than to Campus 2?

Campus 1 got 37.4% of campus 1 mails, 31.9% of campus 2 mails and 48% of campus 3 mails.
Campus 2 got 39% of campus 1 mails, 44.9% of campus 2 mails and 24% of campus 3 mails.

We don't know how many mails each of campus 1, 2 and 3 had sent out. 
If campus 1 and 2 sent out about 100 mail each while campus 3 sent out 100,000 mails, then campus 1 got more mails. (because it got much more of campus 3 mails)
If campus 1 and 3 sent out 100 mails each but campus 2 sent out 100,000 mails, then campus 2 got more mails. (because it got much more of campus 2 mails)
So we can't say who got more mails.

Select  No

siya1998 · Answer

Hi, if no if the right answer for the first question the same can be done for the 2nd question. In every case we are not aware of the number of emails sent by each of the campus to every other campus

cheshire · Answer

It's based off of percent.

soniasw16 · Answer

With this logic, why is it a yes for the second Q?

egmat · Answer

soniasw16   Here's the key difference with Question 2:

Look at the percentages for Campus 3 vs Campus 4 in  EACH  column:

From Campus 1:   13\%  vs  6.5\%  → Campus 3 receives more 
  From Campus 2:   7\%  vs  2.3\%  → Campus 3 receives more 
  From Campus 3:   20\%  vs  4\%  → Campus 3 receives more

Campus 3 receives a  higher percentage from EVERY single source campus . This means that regardless of how the email volumes are distributed across Campus 1, 2, and 3, Campus 3 must receive more total emails than Campus 4.

Why Question 1 is different:

When you compared Campus 1 vs Campus 2 as destinations, the percentages are  mixed —some favor Campus 1, others favor Campus 2. This creates the volume-dependency.

Hope this answers your question!

Researchers collected and studied emails sent by staff at three campus

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Emails to	Campus 1	Campus 2	Campus 3
	Emails from
Campus 1	37.4%	31.9%	48%
Campus 2	39%	44.9%	24%
Campus 3	13%	7%	20%
Campus 4	6.5%	2.3%	4%
Campus 5	0%	2.3%	0%
External	6.5%	11.65%	4%

YES	NO
		Were more of the emails sent to Campus 1 than to Campus 2?
		Were more of the emails sent to Campus 3 than to Campus 4?
		What percentage of the emails to Campus 5 were sent from Campus 2?

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Researchers collected and studied emails sent by staff at three campus

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