IMO B, it is the one on which the conclusion depends, if this false then the conclusion will not hold true

I think E is the correct answer. We need this assumption to compare the differences in the tips given by same group of people on the bills with and without thank you note.

IMO E...The conclusion is that tip will increase with a Thank You note and if all the patrons present higher tip with a Thank You note on the bill then tip amount will certainly increase..

OA please?

In a study conducted in PennsylvaniaServers 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?

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.


IMO E

It points out the assumption the difference in tips given with and without thank you note...

The conclusion of this argument is a prediction. All predictions assume that relevant events in the future will remain unchanged (i.e. nothing unexpected is going to happen that would jeopardize the prediction from coming to pass).

(B) states that "Regularly seeing "Thank you" written on their bills would not lead restaurant patrons to revert to their earlier tipping habits." Let's use Kaplan's denial test to see what impact the opposite of this statement would have on the argument:

"Regularly seeing thank you on bills WOULD lead to patrons reverting to their old tipping habits."

If tippers go back to tipping the same as they always did before the friendly message, then servers' income from tips wouldn't increase - it would remain the same.

Since the denial of (B) stops the prediction from coming true, (B) MUST BE TRUE in order for the argument to make sense: choose (B).

(D) says: "The rate at which people tip food servers in Pennsylvania Does not vary with how expensive a restaurant is."

Let's change that to " The rate at which people tip food servers in Pennsylvania DOES vary with how expensive a restaurant is."

Do we care that the rate varies from restaurant to restaurant? Not at all - the prediction is that "their average income from tips would be higher than it otherwise would have been", which only relates to each individual server's tip income. So, the opposite of (D) doesn't affect the conclusion, therefore (D) is irrelevant.

(E) says: "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."

Does it matter that "virtually all of them" left larger tips than they otherwise would have? What if "60% of them left larger tips than they otherwise would have"? Wouldn't that have still resulted in larger average incomes for the servers? Yes, it would have. Since it doesn't have to be true that it was "virtually all of them", (E) is not a MUST BE TRUE, so eliminate (E).

How do you weaken E?If virtually all patrons DO not leave a larget tip then the earnings won't increase.Does'nt that weaken the statement??Please help.

Stuart Kovinsky wrote:The conclusion of this argument is a prediction. All predictions assume that relevant events in the future will remain unchanged (i.e. nothing unexpected is going to happen that would jeopardize the prediction from coming to pass).

(B) states that "Regularly seeing "Thank you" written on their bills would not lead restaurant patrons to revert to their earlier tipping habits." Let's use Kaplan's denial test to see what impact the opposite of this statement would have on the argument:

"Regularly seeing thank you on bills WOULD lead to patrons reverting to their old tipping habits."

If tippers go back to tipping the same as they always did before the friendly message, then servers' income from tips wouldn't increase - it would remain the same.

Since the denial of (B) stops the prediction from coming true, (B) MUST BE TRUE in order for the argument to make sense: choose (B).

(D) says: "The rate at which people tip food servers in Pennsylvania Does not vary with how expensive a restaurant is."

Let's change that to " The rate at which people tip food servers in Pennsylvania DOES vary with how expensive a restaurant is."

Do we care that the rate varies from restaurant to restaurant? Not at all - the prediction is that "their average income from tips would be higher than it otherwise would have been", which only relates to each individual server's tip income. So, the opposite of (D) doesn't affect the conclusion, therefore (D) is irrelevant.

(E) says: "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."

Does it matter that "virtually all of them" left larger tips than they otherwise would have? What if "60% of them left larger tips than they otherwise would have"? Wouldn't that have still resulted in larger average incomes for the servers? Yes, it would have. Since it doesn't have to be true that it was "virtually all of them", (E) is not a MUST BE TRUE, so eliminate (E).

Dear Stuart,
I heard that we should prephrase possible correct answer before going to answer choices. Do you do so. Please, detail your prephrasing process step by step. We want to learn the way you attack the problem not only your explanation of the correct answer.