In a study conducted in Pennsylvania, servers in various restaurants wrote "Thank you" on randomly selected bills before presenting the...
GMAT Critical Reasoning : (CR) Questions
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?
Passage Analysis:
| Text from Passage | Analysis |
|---|---|
| In a study conducted in Pennsylvania, servers in various restaurants wrote "Thank you" on randomly selected bills before presenting the bills to their customers. |
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| Tips on these bills were an average of three percentage points higher than tips on bills without the message. |
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| 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. |
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Argument Flow:
The argument moves from specific study evidence to a broad real-world prediction. We start with controlled experiment results, then jump to what would happen if this practice became regular behavior.
Main Conclusion:
If Pennsylvania servers regularly wrote "Thank you" on bills, their tip income would be significantly higher than without this practice.
Logical Structure:
The argument assumes that one-time study results will directly translate to long-term real-world outcomes. It connects limited experimental evidence (random "Thank you" messages) to a broader behavioral change (regular practice) and expects the same positive results.
Prethinking:
Question type:
Assumption - We need to find what the argument takes for granted. The argument jumps from a one-time study result to predicting regular long-term income benefits.
Precision of Claims
The argument makes precise quantitative claims (3 percentage points higher tips) and a broad qualitative prediction (significantly higher average income from regular use).
Strategy
Look for gaps between the study conditions and the conclusion. The study tested random one-time messages, but the conclusion assumes regular use would work the same way. We need to identify what must be true for this leap to work - essentially, what could make the conclusion false while keeping the study facts intact.
The argument doesn't distinguish between regular patrons and occasional patrons in its conclusion. The study was conducted on randomly selected bills, and the conclusion applies to all Pennsylvania servers getting higher tips from regular "Thank you" messages. Whether the impact differs between regular and occasional patrons isn't relevant to the argument's logic - the conclusion would still hold even if the impact varied between these groups.
This directly addresses the critical gap between the study's one-time results and the conclusion about regular practice. The study showed that random "Thank you" messages increased tips, but the conclusion assumes regular use would maintain this effect. The argument must assume that customers won't become accustomed to seeing "Thank you" regularly and revert to their previous tipping habits. If customers did get used to it and tip normally again, the conclusion that regular practice leads to significantly higher income would be false. This assumption is necessary for the argument to work.
The argument doesn't need to assume anything about what the "Thank you" message reminds customers of or why it works. The mechanism behind the increased tipping is irrelevant - whether customers think about server income, feel appreciated, or have any other reason doesn't matter. The argument only needs the effect to continue working, not any specific explanation for why it works.
Restaurant expense levels aren't mentioned in the argument. The study results showed a 3 percentage point increase regardless of restaurant type, and the conclusion applies broadly to Pennsylvania servers. Whether tipping rates vary by restaurant expense level doesn't affect the argument's logic about "Thank you" messages increasing tip income.
The argument is based on average results (3 percentage points higher on average), not on virtually all patrons leaving larger tips. Even if some customers weren't affected by the "Thank you" message, the conclusion about significantly higher average income could still be valid as long as the overall average increase is maintained with regular use.