LR Problem Set #4, Q: 299

[moshei24]

I'm pretty sure that I understand this question; I just want to check my understanding.

Is the answer C because this question contains causal reasoning with the cause being dropping the blood and the effect being that it's much less than 9.5, so in C when it says that the effect is 9.3, it's showing that there's an alternate effect for the cause?

Thanks,
Moshe

[Justin Eleff]

I wouldn't say this is a causal reasoning-based question, really. It's more straightforward than what you're describing. This expert witness has based testimony on ten specific trials of the same test, drawing a conclusion from the results of those ten trials. So when the eleventh trial described in (C) comes up, and the results are contrary to the basis for the expert's conclusion (9.3 cm squared is obviously very close to 9.5, and very far away from the 4.5 to 4.8 range the expert refers to), the conclusion itself is cast into doubt. This is more in the realm of weakening a QUALIFIED conclusion than any CAUSAL REASONING. The conclusion comes from the first ten trials' worth of data; the eleventh trial says maybe we shouldn't have based any conclusion on those ten alone.

[moshei24]

So the answer is calling the data into question? And the conclusion is saying that much lower is the only thing that occurs? It's not saying that it usually occurs?

[Justin Eleff]

The expert's conclusion is phrased pretty definitively: "I conclude that a single drop of the defendant's blood stains much less than 9.5 cm squared of the fabric." There isn't any USUALLY about that; he isn't saying it's true of MOST drops of the defendant's blood. Any drop at all will stain less than the stated area. So the answer choice calls the conclusion into question by giving us reason to believe that the expert is simply wrong.

Note that this isn't really calling the data itself into question -- we're not saying the expert did not conduct ten trials, nor that the stains in those trials were larger than reported. Instead we're saying, maybe those trials were not entirely representative of all likely possibilities. The expert can have his ten smaller-stain trials, but we can also have our eleventh larger-stain trial. The data can coexist, but now the expert's conclusion is in fact phrased too definitively.

[moshei24]

Aha, I see. That's what I wasn't sure about - if it was definitive statement or a most statement. Now that I see it's definitive, I understand. The eleventh drop shows that it actually isn't definitive like the expert witness said.

Thanks!