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 all servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, tips left in Pennsylvania would increase by about three percentage points, on average.

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

A. No more than a small proportion of food servers in Pennsylvania currently write “Thank you” on restaurant bills.

B. Most patrons of Pennsylvania restaurants will notice the written “Thank you” on their bills.

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. The “Thank you” messages will have the same impact on regular restaurant patrons as they will on occasional patrons.

MartyMurray · Answer

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 all servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, tips left in Pennsylvania would increase by about three percentage points, on average.

Key to getting an Assumption question correct is noting the conclusion, the support, and how the reasoning of the argument works.

Conclusion:

if all servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, tips left in Pennsylvania would increase by about three percentage points, on average

Supporting premise:

Tips on these bills (with "Thank you" written on them) were an average of three percentage points higher than tips on bills without the message.

One aspect of the reasoning that we may notice is that it jumps from evidence involving a sample of bills to a conclusion about "all" bills.

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

The correct answer to this Assumption question will state something that must be true for the evidence involving a sample of bills to support the conclusion about all bills.

A. No more than a small proportion of food servers in Pennsylvania currently write “Thank you” on restaurant bills.

This choice is interesting

After all, if MORE than a small proportion of servers already write "Thank you" on bills, then, even though the premise is true, the conclusion likely isn't. After all, in that case, even if the notes cause higher tips, many servers are already writing them. So, only servers who were not already writing "Thank you" would experience increases in tips. Consequently, the average increase would be less than three percentage points since many servers' tips would not increase at all.

So, for the argument to work, it must be true that NO more than a small percentage of servers already write "Thank you" on bills.

Keep.

B. Most patrons of Pennsylvania restaurants will notice the written “Thank you” on their bills.

This choice is tricky because it could seem that, for tips to increase as predicted, most patrons would have to notice the message.

Notice, however, that the conclusion is that tips would increase by about three percentage points. Such a small increase could occur even if most patrons don't notice the messages. As long as some patrons notice the messages, tips could increase by that much.

Furthermore, there is the evidence that, in the test sample, the tips on bills with the message were, on average, three percentage points higher. So, the evidence indicates that a sufficiently great proportion of patrons notice the messages for a three-percentage-point increase to occur.

Thus, this argument works regardless of whether this choice is true.

Eliminate.

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

This specific information on a possible reason why the messages work isn't necessary.

After all, the argument works even if the tips are higher for some reason other than the one presented this choice.

Eliminate.

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

This is not required.

After all, even if the rate at which people tip does very from restaurant to restaurant, the average rate could still increase by an average of three percentage points.

In other words, variation in tips wouldn't prevent an average increase in tips from occurring.

Eliminate.

E. The “Thank you” messages will have the same impact on regular restaurant patrons as they will on occasional patrons.

The argument works regardless of whether this choice is true.

After all, the evidence isn't that tips from "regular" patrons were higher when the message was on their bills. It's that tips were higher on average on bills with the message.

So, regardless of whether the impacts on different kinds of patrons are the same, that same overall average impact could be expected to occur if the messages were on all bills.

Eliminate.

Correct answer:   A

guddo · Answer

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 all servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, tips left in Pennsylvania would increase by about three percentage points, on average.
 
 Which of the following is an assumption on which the argument relies?

The argument moves from a study result to a statewide prediction. The study shows that adding “Thank you” increased tips by about three percentage points compared with bills without the message.  For the statewide average to rise by about that much , most bills in Pennsylvania must currently be bills  without  such a message.

A. No more than a small proportion of food servers in Pennsylvania currently write “Thank you” on restaurant bills.

This is correct. If many servers already write “Thank you,” then the practice is already built into current tipping levels, so making all servers do it would not raise average tips by about three percentage points.

B. Most patrons of Pennsylvania restaurants will notice the written “Thank you” on their bills.

This is not required. The study already showed an effect; the argument does not need to assume exactly how many patrons consciously notice the message.

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

This is not required. The message may increase tips for some other reason.

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

This is not required. Tip rates can vary by restaurant price level, as long as the “Thank you” effect is still broadly applicable.

E. The “Thank you” messages will have the same impact on regular restaurant patrons as they will on occasional patrons.

This is too specific. The argument does not need identical effects across these two groups.

Answer: (A)

thisisakr · Answer

Help me eliminate B, if the patrons aren’t noticing will it not make the argument fail

guddo · Answer

B is not required because the study already showed that bills with “Thank you” produced higher tips.

So the argument does not need to separately assume that most patrons notice the message. Maybe many notice it, maybe only some notice it, or maybe the effect works subconsciously. The exact mechanism does not matter.
 
Negating B does not kill the argument : even if most patrons do not notice the message, the average tip could still rise by about three percentage points if enough patrons are influenced by it.

The real issue is whether the message is already common. If it is already common, then making everyone do it will not create a new  statewide increase .

MartyMurray · Answer

My explanation above now includes detail on why (B) is incorrect.

egmat · Answer

Hi thisisakr,

Your instinct makes sense: it  feels  like patrons must notice the "Thank you" for tips to go up. But here's the key move that lets us cut B.

The study already includes whatever noticing actually happens.  The servers wrote "Thank you" on real bills and handed them to real customers, and those bills came back with tips about  3  points higher. Whatever fraction of patrons noticed (or didn't) is already baked into that result. The argument isn't predicting a noticing rate - it's just saying: do the same thing statewide, get the same observed effect.

So B isn't something the argument needs to be true. The effect was measured under normal conditions; the argument only assumes that rolling it out to all servers reproduces that measured effect. It never has to assume "most patrons will notice."

Quick test - negate B:  Suppose most patrons do  not  notice the "Thank you." Does the argument fall apart? No - the study still recorded a three-point lift even with whatever noticing rate existed. The conclusion survives. When the negation of a choice doesn't break the argument, that choice is  not  a required assumption.

Compare that with  A : negate it (many servers  already  write "Thank you"), and now making everyone do it adds almost nothing new - the three-point increase vanishes. That negation  does  break the argument, which is exactly why A is the assumption.

The habit to build:  for an assumption choice, ask "if this were false, does the conclusion collapse?" B fails that test; A passes it.

Answer: A

Usernamevisible · Answer

1. PRETHINK (Before Looking at Choices)
 Conclusion:  If  all  servers write “Thank you,” average tips across Pennsylvania will rise by ~3 percentage points.
 Evidence:  In a study, bills with “Thank you” got tips 3 percentage points higher than bills without it.
Likely assumptions
 
  Most servers are not already writing “Thank you.” 
 
 Otherwise statewide adoption would affect only a small number of bills.  
 
  Customers generally notice/read the message. 
 
 If customers do not notice it, the effect cannot occur.  
 
  The study effect would continue when the practice becomes widespread. 
 
 The 3-point increase is not just a special-study phenomenon.  
 
  The restaurants/customers in the study are reasonably representative of Pennsylvania. 
 
 The observed effect can be generalized statewide.

2. OPTION ANALYSIS
A. No more than a small proportion of food servers in Pennsylvania currently write “Thank you” on restaurant bills.
 Analysis 
This is the assumption.
The conclusion predicts that if  all servers  start doing it, statewide tips will increase by about  3 percentage points .
That only works if most bills currently  do not  contain the message.
If many servers already write “Thank you,” then a large portion of customers are already receiving the treatment. Converting the remaining servers would produce  much less than a 3-point statewide increase .
 Negation test: 
Suppose a large proportion of servers already write “Thank you.”
Then moving to universal adoption would affect only a small number of bills, making the predicted statewide increase of about 3 percentage points unsupported.
 Correct

B. Most patrons of Pennsylvania restaurants will notice the written “Thank you” on their bills.
 Analysis 
Tempting but too strong.
The study already found a 3-point increase when the message was written. That means enough customers noticed it for an effect to occur.
The argument does  not  need  most  patrons to notice it.
Maybe only 40% notice it, and that same effect still produces the observed 3-point increase.
 Negation test: 
Suppose fewer than most patrons notice it.
The study result could still be true and the statewide prediction could still hold.
Not required.
 Wrong

C. The written “Thank you” reminds restaurant patrons that tips constitute a significant part of the income of many food servers.
 Analysis 
This proposes a  specific mechanism .
The argument only needs the message to increase tips.
It does  not  matter  why  it works.
Maybe customers tip more because:
 
 it feels polite, 
 it creates goodwill, 
 it personalizes the interaction, 
 it signals effort.
Any mechanism would support the conclusion.
 Negation test: 
Suppose the message does  not  remind customers about servers' income.
The message could still increase tips.
Not necessary.
 Wrong   
 
D. The rate at which people tip food servers in Pennsylvania does not vary with how expensive a restaurant is.
 Analysis 
Irrelevant.
The argument compares:
 
 bills with message 
 bills without message
The claim concerns the effect of the message.
Variation in tipping rates across expensive vs cheap restaurants does not matter unless the argument were comparing restaurant types.
Even if tipping rates vary dramatically by restaurant price, the message could still add roughly 3 percentage points.
 Wrong

E. The “Thank you” messages will have the same impact on regular restaurant patrons as they will on occasional patrons.
 Analysis 
Another unnecessary subgroup claim.
The argument needs an overall statewide effect.
The impact does not need to be identical across groups.
Maybe:
 
 regular patrons increase tips by 2 points, 
 occasional patrons increase tips by 5 points.
A statewide average increase could still be around 3 points.
 Negation test: 
Suppose the impacts differ.
The conclusion can still hold.
Not required.
 Wrong

3. 725+ Scorer Internal Thought Process (10–15 seconds)

4. TAKEAWAYS
 
  Pattern:  Experiment → statewide prediction. 
  Recognition Trigger:  Conclusion assumes the treatment is not already widely in place. 
  Key Gap:  Current baseline adoption rate. 
  Elimination Lesson:  Mechanism answers ("why it works") are usually unnecessary unless the conclusion depends on that mechanism. 
  Elimination Lesson:  "Same effect across subgroups" is rarely required when the conclusion only needs an overall average effect.
 Answer: A

SS3003 · Answer

Can you help in Negating D - if you negate D that regular patrons will have tip more then the argument breaks . This is by pre thinking the assumption that the passage assumes that it is not the rareness of the "thank you" but just writing the "thank you: has the higher tipping effect.

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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