Thanks for the invitation to chime in here - and great use of the Assumption Negation Technique, Anahatha! That's exactly how I'd look at this one:
We're concluding that THE METHODS to determine the gold content were inaccurate. And we're doing that because that study suggested that there was plenty of gold, but gold wasn't found in the two mining expeditions. Essentially the argument goes:
Study found high gold content, but mining expeditions found no gold. Therefore, study methods were wrong.
The best part of that Assumption Negation Technique, to me, is that it turns these questions into a type of "weaken" question - you're looking to attack the argument. Immediately I think that this argument is weak. Why? Because it may not have been the methods that were wrong...it could have been some other flaw in the study situation. Perhaps there was one small pocket of gold that he tested (correctly) and by the time they mobilized the expedition someone had already gotten to it. Or perhaps someone tampered with the sample (as E will elude to) to convince Elizabeth to fund the operation.
If you negate choice E, it directly weakens that conclusion as we just proposed above:
Gold WAS (not 'was not') added to the samples before the samples were examined.
This hits that tampering possibility - if the samples were contaminated, even the most accurate study methods would provide a false result. And so E is an assumption that the original argument made - that it wasn't a tampered sample, but rather a faulty test.
For assumption questions, it's important to read the argument critically; the correct answer seldom provides compelling NEW evidence...it usually just clarifies the existing evidence in a way to make it more effective. So if you're already poking at the argument for flaws/weaknesses, you'll better see the need for that supporting evidence in the correct answer. And if you use Assumption Negation, you can turn it directly into a weaken question, and we tend to be really good at those. Who among us doesn't like to criticize?
Brian Galvin
GMAT Instructor
Chief Academic Officer
Veritas Prep
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