In a study conducted in Pennsylvania, servers in various restaurants

Question

In a study conducted in Pennsylvania, servers in various restaurants wrote “Thank you” on randomly selected bills before presenting the bills to their customers. Tips on these bills were an average of three percentage points higher than tips on bills without the message. Therefore, if servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, their average income from tips would be significantly higher than it otherwise would have been.

Which of the following is an assumption on which the argument relies?

B. Regularly seeing “Thank you” written on their bills would not lead restaurant patrons to revert to their earlier tipping habits
.

Which of the following is an assumption on which the argument relies?

(A) The “Thank you” messages would have the same impact on regular patrons of a restaurant as they would on occasional patrons of the same restaurant

(B) Regularly seeing “Thank you” written on their bills would not lead restaurant patrons to revert to their earlier tipping habits

(C) The written “Thank you” reminds restaurant patrons that tips constitute a significant part of the income of many food servers

(D) The rate at which people tip food servers in Pennsylvania does not vary with how expensive a restaurant is

(E) Virtually all patrons of the Pennsylvania restaurants in the study who were given a bill with “Thank you” written on it left a larger tip than they otherwise would have.

11MBA · Accepted Answer

The argument states that waiters who write "thank you" on the bill on average get 3% higher tips on checks than those who don't. Therefore, the waiters believes that if they will get a more tips if they write "thank you" on each receipt. The questions asks for the assumption that the waiter's belief relies upon.

A. The "Thank you" messages would have the same impact on regular patrons of a restaurant as they would on occasional patrons of the same restaurant.  The question does not distinguish between occassional and regular patrons. It only states that the patrons who see "Thank you" pay tip 3% higher than those who don't have "Thank you" on their checks.

B. Regularly seeing "Thank you" written on their bills would not lead restaurant patrons to revert to their earlier tipping habits. If this is true then it would not undermine the conclusion that people who see "thank you" will tip more.

C. The written "Thank you" reminds restaurant patrons that tips constitute a significant part of the income of many food servers.  This statement is not necessary because it touches upon the reason why people might pay more. ie. Patrons could be paying more bc the "Thank you" makes them think that their waiter is friendlier. This does not undermine the conclusion.

D. The rate at which people tip food servers in Pennsylvania Does not vary with how expensive a restaurant is.  Out of scope.

E. Virtually all patrons of the Pennsylvania Restaurants in the study who were given a bill with "Thank you" written on it left a larger tip than they otherwise would have. This is not an assumption made to draw the conclusion. This is the result of the study.

mbaiseasy · Answer

Premise: RANDOM TY NOTE -> INCREASED TIPS
Conclusion: REGULARLY WRITING TY NOTE -> INCREASED TIPS

GAP: RESULT THAT WAS OBSERVED ON "RANDOM" ACTS WILL HAPPEN WHEN THIS IS DONE "REGULARLY"
  
Which of the following is an assumption on which the argument relies?

A. The "Thank you" messages would have the same impact on regular patrons of a restaurant as they would on occasional patrons of the same restaurant.
  No need to assume on the behavior of regular vs occasional patrons... The issue is Random TY Writing vs. Regularly Writing TY Noes..

B. Regularly seeing "Thank you" written on their bills would not lead restaurant patrons to revert to their earlier tipping habits.
  If Regularly doing so will lead to reverting to earlier tipping THEN the conclusion is invalid. This is the assumption.

C. The written "Thank you" reminds restaurant patrons that tips constitute a significant part of the income of many food servers.
  What TY note reminds the customer was not mentioned in the stimulus

D. The rate at which people tip food servers in Pennsylvania Does not vary with how expensive a restaurant is.
  We are concerned with average tips collected. The variation is not our concern.

E. Virtually all patrons of the Pennsylvania Restaurants in the study who were given a bill with "Thank you" written on it left a larger tip than they otherwise would have.
  All patrons is a stretch.

Answer: B

cialit0506 · Answer

I like your explanations on B as that was how I thought it should be. And the OA is B too.

But, is there anything wrong with A? Can't A function as an assumption too?

You see, if the impact was the same for both kinds of patrons, wouldn't A become an assumption that supports the argument?

I heard of the technique "If Yes/No" analysis. Shall we use it to go through choices A and B? From what ppl say, if an answer choice could support/weaken an argument whenever it switches from "If Yes" to "If No" or vice versa, then that is probably a correct answer. Choices that could not support or weaken whenever you use "If Yes" or "If No" would not be a correct answer.

For A

If Yes, A supports/strengthens the argument.

If No (ie. impact is different for both sets of patrons; some might tip a bit more and some a bit less, but ultimately all of them on average would tip more than previously), A cannot weaken the statement either. In fact, if you look closely, B actually still supports the statement.

Since both "If Yes/No" can  only  support the statement (Even when you swith to "If No", you still cannot weaken it), then this is probably not the answer.

For B  
If Yes, B supports the statement. The reasonings are as provided by the previous posts

If No, B weakens the argument instantly. Say, if the patrons would revert back to tipping less, then the argument weakens.

Since both "If Yes/No" can support and weaken the argument, then   this is probably the correct answer.

Hmm.... please let me know if you agree with my line of reasoning as it can be a bit hard to put it in words.

Thanks.

perfectstranger · Answer

If regularly seeing “Thank you” written on their bills would lead to divert the customer to their earlier tipping habits then the conclusion would not hold. Clearly B

11MBA · Answer

Here's my reasoning for why it's not E. The conclusion is that if waiters write "thank you" on the checks, then they will receive a higher tip. The conclusion is drawn from the fact that in a previous study those who wrote "thank you" received 3% higher tips than those who did not.

According to E. Virtually all patrons of the Pennsylvania Restaurants in the study who were given a bill with "Thank you" written on it left a larger tip than they otherwise would have. This not an assumption that the conclusion depends on. Not all the patrons need to leave more tip than they otherwise would have in order for the conclusion to be drawn that writing "thank you" will increase the tip. The question states ON AVERAGE those who had "thank you" tipped 3% higher. Perhaps only half of the people left a higher tip. Perhaps only a quarter left a higher tip. Or perhaps only one person left a higher tip (a really really big tip). The number of patrons who left a higher tip does not matter in this argument. It's merely stated that ON AVERAGE tips were 3% higher. If the "thank you" induced anyone at all to leave a higher tip then they would have, then the overall tip would be higher.

Vannbj, I understand your reasoning that it's possible that the patrons who got "thank you" on their bill were incidentally the ones who also got better treatment from the waiters. Therefore the better service and not the "thank you" per say was the reason for the higher tip. However, statement E says that virtually all patrons of the Pennsylvania Restaurants in the study who were given a bill with "Thank you" written on it left a larger tip than they otherwise would have. Yes this argument does distinguish that the "thank you" was the cause of the higher tip, but like I mentioned before, it's not necessary for virtually all of the patrons to tip more in order for the conclusion to be drawn.

sudish · Answer

Heres the explanation:

Option A  states that both regular patrons and occasional patrons of the restaurant will be impacted in a similar way on seeing the 'Thank You' note. However, the impact is not mentioned clearly and hence this is out of scope.

Option B  states that seeing the 'Thank You' note regularly would not lead restaurant patrons to revert to their earlier tipping habits. Thus, this option eliminates the possibility that would weaken the argument. In other words, using the  assumption negation  technique, we can see that if the patrons revert to their earlier tipping habits on seeing the note regularly, the average income of the servers would not be higher. This contradicts the original argument which concludes that higher tipping on seeing the 'Thank You' note will lead to a higher income for the servers. So this is the correct answer choice.

Option C seems to be a bit far fetched because in order for this option to be correct, we need to assume that the patrons would tip higher as they would think, on seeing the thank you note, that the tip is a significant part of the servers income.

Option D  seems to be out of scope as we are not concerned with how expensive or less expensive a restaurant is.

Option E  seems to be irrelevant as well because it adds on to the given premise that tip was high when the bill was accompanied by a Thank You note.

Hope this helps.

Cheers!

sanjuro9 · Answer

We do one study and conclude that we can continue the practice "regularly" and continue to reap the same benefits.
B is the only assumption that is required to make this conclusion.

A) not a necessary assumption. even if it had different effects and all regular patrons could have tipped much more to generate the extra 3% in tips or it could have been the other way around.
C) Whether the notes remind the patrons of something, insults them or applauds their generosity is outside this discussion. We are only focused on the end result of more tips.
D) The tipping rate could be different for restaurants. We are comparing previous tipping rate at the same restaurant, not across various restaurants.
E) All (or for that matter significant) number of patrons don't have to leave a larger tip. Only few may be leaving large enough tip to get the "average" 3% higher tipping rate.

hope this helps.

12bhang · Answer

In a study conducted among servers in restaurants in Canada, it was observed that the tips on bills with a "Thank you " note attached were on an average 3 percentage points higher than those without the note. Thus, regularly writing Thank you on the bills will increase the average income from tips significantly. 
What is the assumption on which the argument depends.

A) the thank you would have the same effect on regular patrons of the restaurant as on the occasional ones
B) regularly seeing thank you written on the bill will not make the customers change their tipping habits.
C) The thank you reminds restaurant patrons that tips constitute a major part of the income to the servers
D)The rate at which the customers tip does not vary with how expensive the restaurant is
E) Virtually all patrons of the restaurant who were given a bill with a thank you written on it left a larger tip than they would have.

The clear assumption in this question is that the patrons of the restaurant will continue their tipping habits,even after regularly seeing a Thank you written on the bill.

Considering choice A: If the regular patrons contribute towards a larger portion of the revenue earned by the restaurant, the tips that they give will also constitute a significant part of the total income received from tips. In this case, if regular patrons are not affected by the new thank you note, average revenues might not go up  significantly - the key word here. 
 
On the other hand, if regular patrons constitute a very small proportion of the customer base, then whether they tip higher or not does not matter at all as far as significant increase in revenues from tips are concerned.

Regular patrons total customers 
20 1000 -very small effect
700 1000 -significant effect

So, does the statement as it is stand as a strengthener?

Also, choice A says that the thank you will have the same effect on both regular ones and non regular ones? What effect is this, we do not know. It could mean that both are affected in a way that they tip higher or both are affected in a way that the thank you has no effect. Or are we to assume that the effect being talked about in this option is that they will tip higher?

Suppose we change this statement- " Regular patrons are as likely to tip higher than are occasional patrons"-
 
Now, we don't know how likely the occasional patrons are to tip. If the likelihood is high- revenues will go up. If not, then revenues will not go up.

What do you think?

Could you suggest possible strengtheners?

egmat · Answer

In the context of the passage, "significant" means around 3%. The argument can't sensibly refer to a sample in which tips increased by 3% and say that in the future it will be a 10% increase. 
Secondly, we don't know how much of the revenue of the restaurant or tips of the servers are generated from regular patrons or from occassional patrons, so comparing them does not help us any bit. We don't know about any of these and the option statement makes a comparison between these two.

Whatever you do with option A, it is going to remain on OFS answer choice till it keeps comparing regular patrons with occasional ones. We don't know about any of these. What would we gain by a comparison of these two? If we had known about tipping habits of one category of guys, then, by comparison, we might have gained something but as is, option A is completely non-nonsensical and out of scope.

Thanks,
Chiranjeev

blueseas · Answer

conclusion: write regularly THANK YOU on restaurant bills ===> income with tip will rise significantly i.e 3 percent (as per the argument)

premise:  study conducted on various restaurant ==>bills with thank you earned 3 percent more tips.

A. The "Thank you" messages would have the same impact on regular patrons of a restaurant as they would on occasional patrons of the same restaurant. ==.whatever is the effect of patrons whether they are regular or occasional patrons==>end result is that we have received 3 percent more tip which is already proved in premise...==>so this has no effect.
 
B.  Regularly  seeing  "Thank you" written on their bills would not lead restaurant patrons to revert to their earlier tipping habits. 
 now according to premise we gained 3 percent increase on tip having thank you message in an experiment.
that was only in the experiment period.what is different in that experiment period and the conclusion?
the only difference is that time duration==>THE experiment was/must be for some period of time==>in conclusion we are putting THANK YOU message regularly....so thats the only difference if that factor doesnt affect then or conclusion is perfect.hence this is correct
 
C. The written "Thank you" reminds restaurant patrons that tips constitute a significant part of the income of many food servers.
we are not concerned what it reminds or not ==>if it reminds then it was reminding too during experiment also and viceversa.
so if you negate==>it doesnt remind===>this means experiment was successfull in the absence of reminder...so this one doesnt affects conclusion.

D. The rate at which people tip food servers in Pennsylvania Does not vary with how expensive a restaurant is.
 again same as A...we are not concerned how it affects in different types of restaurant ==>end result is we are getting 3 percent increase in tip.
hence out of scope.

E. Virtually all patrons of the Pennsylvania Restaurants in the study who were given a bill with "Thank you" written on it left a larger tip than they otherwise would have.  ==>again conclusion doesnt depends on this because whether the increment was because of ALL or because of SOME we are not concerned.

hope this helps

Ilhomjon98 · Answer

Hi  IanStewart

Could you please help with this question?

I could understand why (E) is wrong.

We don't neccessarily have to assume that Virtually all patrons in the study who were given a bill with “Thank you” written on it left a larger tip than they otherwise would have. The conclusion would still be ok even if 40% of those patrons left a larger tip than usual.

Yet, I couldn't completely comprehend why (B) is correct.

Could you please explain why (B) is correct?

Thank you very much beforehand!

IanStewart · Answer

Yes, E is wrong because the argument is only about averages. As long as tips are larger on average, the servers make more money, and it doesn't matter if every tip is 3% larger, or if one tip is huge and 99% of tips are unchanged.

Here we have a small-scale experiment which produced a 3% increase in tips. If we're going to translate that to a large-scale experiment (where servers always write 'thank you' on bills), then if we're expecting we'll still see a 3% increase in tips, we're assuming nothing will change as we scale things up. That is, we're assuming customers will behave the same way if they always see 'thank you' on their bill as they did in the small-scale experiment where they were seeing 'thank you' on their bill for the first time (or at least when they only rarely saw 'thank you' on a bill). So that's why B is right.

There are a lot of similar arguments, in the real world and on the GMAT, which make a similar assumption. For example, and this is not based on any actual facts about limes, I'm just inventing a scenario: if a two-week-long study proved that eating a lime every day improved people's moods, and based on that data, dieticians suggested everyone should eat limes every day to improve mood long-term, that conclusion would be assuming that people don't build up a tolerance for or immunity to the happiness-producing effects of limes. That is, the conclusion is assuming when you scale things from a short two-week study to a permanent behaviour, people continue to respond identically. That may or may not be true.

lakshya14 · Answer

(E)? If we write "thank you" or not, they would have still left it?

svasan05 · Answer

Hi Laksya

No, that is not the reason for (E) being incorrect.

The question asks us identify the underlying assumption for the conclusion that, "if servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, their average income from tips would be significantly higher than it otherwise would have been", based on the results of the experiment stated before this statement. Which means, to draw this conclusion from the given results, what assumption  needs to be  true.

Option (E) is not required to be true for this conclusion from these facts ie; given these results, the conclusion is neither strengthened nor weakened whether (E) be true or not. If you negate (E), the conclusion is not negated.

Hope this answers your question.

krndatta · Answer

EducationAisle  sir,

Please evaluate my reasoning.

Option A:- This is incorrect because the argument above does not talk anything about the impact of "Thank you" messages on regular and occasional patrons. The argument does not say that the impact leads to higher tipping. Hence, this is incorrect.

Option B:- This is the correct answer. When negated the conclusion breaks down. Regularly seeing "Thank you" would lead patrons to revert to their old habits. Hence, this would break the conclusion.

Option C:- No impact on our argument. The passage above does not draw a link between reminding and high tipping. Hence, this is incorrect.

Option D:- Incorrect. Varying tipping and restaurant expense does not have any impact on the high tipping. Plus when we negate this option statement we get " The rate varies with how expensive the restaurant is". So our conclusion still stands because we don't know whether that variation is towards the higher side or not. Hence, this cannot be assumed.

Option E:- This is an interesting one. I initially marked this one. This is irrelevant too because this restates the information already mentioned in the passage. How many people left a larger tip is not our concern. We concluded from the study that seeing a thank you leads to higher tipping. Out of all the people in the study all left a larger tip or 70 percent or 50 percent. It doesn't matter. The outcome is that we have concluded something from the study. Hence, this is the incorrect answer.

Please share your two cents on my reasoning above.

Thanks

EducationAisle · Answer

Would agree also note that A is incorrect because the argument does not differentiate between regular patrons and occasional patrons. For example, regular patrons may give 2% extra tip, while occasional patrons may give 4% extra tip, but the argument still holds true.

Sabarni · Answer

Why is it not E, because we have not been prompted in the question that normally also those people would not have tipped a better amount?

MartyMurray · Answer

Here's (E):

(E) Virtually all patrons of the Pennsylvania restaurants in the study who were given a bill with “Thank you” written on it left a larger tip than they otherwise would have.

In a GMAT Assumption question, the correct answer must state something additional that's necessary for the argument to work.

In this case, the argument has already presented the following evidence:

Tips on these bills were an average of three percentage points higher than tips on bills without the message.

That evidence is sufficient to support the conclusion even if what (E) says isn't true. After all, if it's the case that, on average, people left a greater tip when the server wrote "Thank you" on the bill, then it's reasonable to conclude that "if servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, their average income from tips would be significantly higher than it otherwise would have been."

After all, as long as the average tip is bigger, the servers' incomes will be higher, even if not all patrons leave bigger tips.

So, the argument doesn't depend on it being true that virtually all the patrons who were given bills with "Thank you" written on them left larger tips than they otherwise would have. It still works even if that isn't true.

Usernamevisible · Answer

CORE ARGUMENT (ultra-tight)

Evidence: Writing “Thank you” → tips increase by about 3 percentage points (study, random bills)

Conclusion: If done regularly, servers’ average tip income would be significantly higher

Shift: one-time experimental effect → long-term real-world habit

PRETHINK (KEY AREA)

We need assumptions that allow:
short-term experimental bump → sustained real-world income increase

Gap 1 — Habit persistence
Type: Necessary Condition
Customers will not reduce their tipping response after repeatedly seeing “Thank you”.

Gap 2 — No adaptation / diminishing effect
Type: Causation vs Correlation
The increase in tips is caused by the message itself, and this effect does not weaken with repetition.

Gap 3 — Generalization from experiment → real life
Type: Sampling / Representativeness
The behavior observed in the study accurately reflects real-world customer behavior over time.

Gap 4 — No alternative driver during study
Type: Alternative Cause
The higher tips were not due to other factors (such as friendlier service when writing the message).

Gap 5 — Scaling assumption
Type: Scope Shift
A small average increase (3%) per bill translates into a meaningful increase in overall income.

Most critical gap:
People won’t get used to it and ignore it over time

OPTION ANALYSIS (DETAILED)

(A)
FULL:
The “Thank you” messages would have the same impact on regular patrons of a restaurant as they would on occasional patrons of the same restaurant

Analysis:

Compares regular vs occasional customers
Argument never splits customers this way
Even if impact differs, overall income can still rise
Not required

Fails because: irrelevant subgroup comparison

(B) CORRECT
FULL:
Regularly seeing “Thank you” written on their bills would not lead restaurant patrons to revert to their earlier tipping habits

Analysis:

Directly targets repetition problem
If people revert → no long-term increase
Argument needs sustained effect

This is the necessary bridge

(C)
FULL:
The written “Thank you” reminds restaurant patrons that tips constitute a significant part of the income of many food servers

Analysis:

Gives a reason (mechanism)
Argument does not require knowing why it works
Even if reason is wrong, effect could still hold

Fails because: mechanism not required

(D)
FULL:
The rate at which people tip food servers in Pennsylvania does not vary with how expensive a restaurant is

Analysis:

Talks about restaurant price differences
Study compares with vs without message
Price variation does not break conclusion

Fails because: irrelevant factor

(E)
FULL:
Virtually all patrons of the Pennsylvania restaurants in the study who were given a bill with “Thank you” written on it left a larger tip than they otherwise would have

Analysis:

Very strong claim (“virtually all”)
Argument only needs average increase
Too extreme to be necessary

Fails because: overkill requirement

TRAPS + PATTERNS
Mechanism trap → explaining why (C)
Extreme language → “virtually all” (E)
Irrelevant comparison → subgroup split (A)
Background noise → unrelated variable (D)
CONCEPT TAKEAWAY

Pattern:
Experiment → real-world recommendation

Always check:

Will effect persist over time?
Will people adapt or ignore it?

Fast shortcut:
When you see “if done regularly → benefit”
Ask: “Will people get used to it?”

In a study conducted in Pennsylvania, servers in various restaurants

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In a study conducted in Pennsylvania, servers in various restaurants

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