#13 - If retail stores experience a decrease in revenues

[ameliashaffer]

I understand why it is C, but I am confused why we rule D out. I connected the conditional statements as follows:

DR = decreased revenue, AC = attitudes changed, PR = prices risen, SKP = salaries kept pace

DR --> AC or PR
AC Not and PR Not --> DR Not
PR --> SKP Not
SKP --> PR Not

Given the question stem, I combined the chains to be "SKP --> PR Not and AC Not --> DR Not"

Are you not allowed to combine the "SKP --> PR Not" with the "PR Not AC Not ==> DR Not." Doing so gave me Answer D.

Thanks!

[Dana D]

Hey Amelia,

Be careful here - the stimulus says (and you correctly diagrammed) that if there is a decreased revenue, attitudes have changed OR prices have risen.

DR Attitudes changed OR prices have risen

Your error was when you combined the conditional logic as "SKP --> PR Not and AC Not --> DR Not". In MBT questions, the correct answer choice would be one that we can infer from the stimulus alone. However, just based on the stimulus and the additional information of "salaries have kept pace with rising prices", we cannot definitively say that attitudes have not changed. It's possible that they have changed, which would mean stores could still experience a decrease in revenue.

Does that make sense?

[floydbtric@gmail.com]

Hey all,

I don't understand why D is not the correct choice. As by my diagrams which seem to align with everyone else's, it looks to me like it satisfies all the needs.

DR - decreased revenue
Attchange - attitude change
PR - price rise
skp - salaries keep pace

-> Attchange -----> celebrate
DR ------| OR
-> pr ----------------> NO skp


Contrapositives:

(skp----> NO pr)
AND | together ------------------> NO DR
(NO celebrate ------> NO attchange)

The stimulus provides skp (bold):

(skp----> NO pr)
AND | together ------------------> NO DR
(NO celebrate ------> NO attchange)

And D as an answer choice provides:

(skp----> NO pr)
AND | together ------------------> NO DR
(NO celebrate ------> NO attchange)

[Jeff Wren]

Hi floyd,

First, if you haven't done so already, I'd recommend reading the prior explanations on this forum post, as many students had questions about Answer D.

To address your question, I think that you are confusing conditional statements (in the stimulus) with non-conditional statements of fact (in Answer D).

The stimulus tells us that:

If retail stores have a decrease in revenue, then either attitudes towards gifts has changed or prices have risen beyond what people can afford.

This can be diagrammed:

RSDR -> ATGC or PRBPA

(For simplicity, I'm going to hold off on the other conditional statements for now.)

Now if we learn that one of these necessary terms doesn't happen, such as "prices have NOT risen beyond what people can afford" (Not PRBPA), this doesn't tells us anything about RSDR or ATGC. It's possible that retail stores have a decrease in revenue (in which case we'd also know that attitudes towards gifts must have changed), but it's also possible that retail stores did NOT have a decrease in revenue.

We are able to infer that "prices have NOT risen beyond what people can afford" (Not PRBPA) based on the fact that salaries have kept pace with prices using the contrapositive of the third conditional statement in the stimulus, which is why Answer C is correct.

However, as stated above, knowing that one of the possible necessary conditions didn't happen does tells us anything about the original sufficient condition or the other necessary condition.

Answer D is not conditional. It is NOT saying "If attitudes towards gifts have Not changed, then retail stores will Not have a decrease in revenue." Instead it is stating definitely that the other necessary condition did Not happen and the sufficient condition did Not happen, and we have no proof of this at all.

Here's a (hopefully) easier to follow example.

If I went to Hawaii, then I either went surfing or I went scuba diving.

I then tell you that I did not go scuba diving.

Answer D would be saying "I did not go surfing and I did not go to Hawaii." This, of course, is not proven by the fact that I did not go scuba diving.