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Helpful to know | Worked example

Watch a demonstration of one way to approach a question that asks you what additional info would be most useful to know to make an argument valid.

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  • blobby green style avatar for user A A
    Type of Question: Evaluate the Support (Assumption Family)

    Which one of the following would be most useful to know in order to evaluate the support for the archaeologists’ hypothesis?

    (A) whether the traditional techniques for building reed boats were in use at the time Tiwanaku was inhabited

    (B) whether green andacite stones quarried at the time Tiwanaku was inhabited were used at any sites near Copacabana

    (C) whether reed boats are commonly used today on the lake

    (D) whether the green andacite stones at Tiwanaku are the largest stones at the site

    (E) whether the reed boat built for the experimenters is durable enough to remain usable for several years

    (A) is correct

    Here we’re asked a question that has cropped up on recent exams: evaluate the support. Instead of being given specific information that will allow us to strengthen or weaken the argument, we’re asked about a category of information, the answer to which would help us determine whether the argument is any good. We need a good understanding of the core and the gap for these questions, so we’ll start by finding the conclusion.

    In this case, the argument tells us we’re meant to evaluate the support for a hypothesis. The hypothesis, then, is our conclusion. (FYI, when hypotheses appear, they are often the conclusion). Our conclusion, then, is that stones (weighing up to 40 tons and quarried 90 km away) were brought to Tiwanaku by reed boat. The support offered was an experiment that transported a 9-ton stone using local materials and traditional techniques.

    Reed boats constructed from local materials and traditional techniques can transport 9-ton stone --> Stones weighing up to 40 tons probably transported the 90 km by reed boat

    Gaps: There are a few here. Sure, we can transport 9-ton stones, but what about 40-ton stones? Also, just because materials are available today, does that mean they were available way back then? Finally, did these "traditional" techniques originate around or before the construction of the prehistoric city?

    We’re asked for a category of information that would help us determine whether the experiment is supports the hypothesis. Anything addressing one of these gaps would be helpful.

    (B) Out of scope. Who cares whether the green stones were also used around the quarry site? The question is whether they could have been transported by the same technique as used in the experiment. This answer does not help us evaluate whether the experimental support is any good. Eliminate.

    (C) Out of scope. So what if reed boats are common today? Does that tell us whether they were used in prehistoric times to transport enormous stones? No. Eliminate.

    (D) Out of scope. Who cares if the green stones are the largest stones? Does this mean they could or could not be transported by reed boat? No. Eliminate.

    (E) Tempting, if we assume the ancients demanded extended warranties on their rock transportation vehicles. But again, this information is irrelevant. We don’t need the boats to last several years. Wouldn’t a six-month boat allow the ancients to transport stones, for, I don’t know, six months? Eliminate.

    That leaves (A): whether the traditional techniques for building reed boats were in use at the time Tiwanaku was inhabited

    This addresses one of the gaps we saw earlier: whether "traditional" techniques were those in use in prehistoric times. My family has a "tradition" of cooking a Thanksgiving meal on Memorial Day. We’ve only been doing it for ten years, not 2,000. So, "traditional" is kind of ambiguous. If we knew the answer to (A)’s question, we would know whether or not the ancients could have built a boat similar to the one used in the experiment. Therefore, the answer is relevant to evaluating how well the experiment supports the hypothesis. Circle this bad boy.
    (8 votes)
    Default Khan Academy avatar avatar for user
  • blobby green style avatar for user Kai Burley
    (A) whether the traditional techniques for building reed boats were in used at the time Tiwanaku was inhabited

    (B) whether green andacite stones quarried at the time Tiwanaku was inhabited were used at any sites near Copacabana

    (C) whether reed boats are commonly used today on the lake

    (D) whether the green andacite stones at Tiwanaku are the largest stones at the site

    (E) whether the reed boat built for the experimenters is durable enough to remain useable for several years
    (7 votes)
    Default Khan Academy avatar avatar for user
  • blobby green style avatar for user hiedomarleen
    I feel like it's better to read the question before diving into the stimulus.
    (3 votes)
    Default Khan Academy avatar avatar for user

Video transcript

- [Narrator] The ruins of the prehistoric Bolivian city of Tiwanaku feature green andacite stones weighing up to 40 tons. These stones were quarried at Copacabana, which is across a lake and about 90 kilometers away. Archaeologists hypothesize that the stones were brought to Tiwanaku on reed boats. To show this was possible, experimenters transported a 9-ton stone from Copacabana to Tiwanaku using a reed boat built with locally available materials and techniques traditional to the area. Which of the following would be most useful to know in order to evaluate the support for the archaeologists' hypothesis? So which would be most useful to know? Whether the traditional techniques for building reed boats were in use at the time Tiwanaku was inhabited. Well, that seems pretty useful. These researchers, they are using traditional, techniques traditional to the area, but we don't know for sure whether they were used at the time when Tiwanaku was inhabited. If they weren't used at the time that Tiwanaku was inhabited, well, that wouldn't be the way that the Tiwanakans, I guess, would have transported, cuz they wouldn't have had those techniques. So this one is looking pretty interesting. Let's see if we can rule out the other choices. So would it be useful to know whether green andacite stones quarried at the time Tiwanaku was inhabited were used at any sites near Copacabana? Well, no, that wouldn't. That would be interesting, but it's completely possible that Tiwanaku was the only place. Maybe it was some type of a sacred place where they took the trouble of bringing these 40-ton stones and that wasn't really important anywhere else. So this one doesn't seem that. This one doesn't seem like a good choice. So would it be useful in order to support the archeologists' hypothesis, would it be useful to know whether reed boats are commonly used today on the lake? Well, no, we're talking about whether folks, I'm assuming a long time ago used these reed boats at Tiwanaku, or to bring these stones to Tiwanaku. In fact, it would be, it's interesting if reed boats are used today, but it's. It very well they could be using modern boats and it has nothing to do with whether the Tiwanakans used the reed boats. Whether the green andacite stones at Tiwanaku are the largest stones at the site. Well, no, even if they aren't or are the largest stones at the site, it's still makes you want to ask the question, "How did these 40-ton stones get there?" So that doesn't help you think about how they got there. Whether the reed boat built for the experimenters is durable enough to remain usable for several years. No, the Tiwanakans, they might have. Even if these reed boats weren't durable enough, maybe one boat for every crossing of the lake, just so to get one 40-ton stone across. So, this one, the durability doesn't seem to matter. I would have been curious because the researchers transported a 9-ton stone while they're talking about that there were stones weighing up to 40 tons. It would be useful to know whether these techniques could be used to transport something that weighs 40 tons, more than the 9 tons. This is a nice proof of concept, but that wasn't the choices. And so, I do like choice A as the best answer. Whether the traditional techniques for building reed boats were even used at the time Tiwanaku was inhabited. Cuz if they weren't used, then this hypothesis wouldn't carry a lot of weight, so to speak.