Q4 - An anthropologist hypothesized

[WaltGrace1983]

We are looking to strengthen the anthropologist's counter-argument. Thus, we do not care too much about the first part of the stimulus. We are really only interested in the last sentence.

Medicinal powder was tested in acidic solution
→
Results from the test were invalid

So if we want to strengthen this claim, how do we do it? We do it by showing that this acidic solution actually had some effect on the results. We might even be able to think of this question in terms of a necessary assumption, as the author is definitely assuming a connection between the validity of the tests and the acidic solution that the powder was tested in. This seems to be the big gap and, considering this is question 4, let's just move on to the answer choices.

(A) This might show why the anthropologist chose to actually study the powder but it doesn't help us conclude anything about why the test results were invalid. We are probably looking for something discussing the "acidic solution" here.

(B) This hinges on "IF the powder is stored for a long time." Is it stored for a long time? We don't know. Does the activity level of Toxin T matter? No. This is a classic out of scope answer choice - it doesn't strengthen, it doesn't weaken, it is just kind of there.

(C) This looks good! It shows the effect that the acidic solution had on the results. Apparently, when Toxin T (the powder) is put into acidic solution, it becomes undetectable. That's not good! The anthropologist was trying to detect significant amounts of Toxin T! If it is undetectable then it is definitely the case that the results weren't accurate.

(D) We care about this test - not a repeat test - this test. Regardless though, this answer is totally irrelevant anyway.

(E) Uh oh. This looks good too. The "type of analysis" doesn't necessarily refer to being "tested in acidic solution." It could have actually referred to the technique the anthropologist used. In addition, we don't care about "SMALL amounts of Toxin T." We care about a "SIGNIFICANT amount of Toxin T." Let's say that small amounts were undetectable. That's fine. This would still prove the anthropologist's tests as negative because the anthropologist was looking for big amounts.

(C) is correct.

[huskybins]

I guess LSAC test writer assumes there are at least two meanings behind the word "negative result" after a test-- one is the presence of T but showing no toxins, and the other is no presence of T at all. Otherwise, C won't hold and is evidence for what the Chemist considers as a fraud.

The point for me to make here is at least I need to know such kind of assumption in order to get this question right.

[Emmeline Ndongue]

I guess LSAC test writer assumes there are at least two meanings behind the word "negative result" after a test-- one is the presence of T but showing no toxins, and the other is no presence of T at all. Otherwise, C won't hold and is evidence for what the Chemist considers as a fraud.

The point for me to make here is at least I need to know such kind of assumption in order to get this question right.

The problem here is T is the toxin, as the question stem specifically states "toxin T". The negative results meant that whether it indeed contain any toxin T at all (we have no idea about this), the test performed didn't detect it or at least didn't detect "significant amount" of it.