Some really excellent thoughts here from a number of people!
First, I'd like to clear up the issue of 'small sample size' vs 'representativeness' that both
magnusgan and
sujin91 both raised.
A small sample can, theoretically, be perfectly valid - so long as it is representative. The problem, realistically, is that the smaller a sample size becomes, the less likely it is to be truly representative at all. If we somehow knew for sure that 4 particular dermatologists were a perfect reflection of the dermatologist population at large, then surveying exactly 4 would be acceptable - but how in the world would we ever know that?
So, the practical result of all of this is that as sample sizes go toward the
very small, the reliability becomes more and more tenuous.
raziel Wrote:In this case, some errors can be: (1) Assuming that what dermatologist say they like best is what is best for the consumer (2) Assuming that the dermatologists prefer the cream because it has desirable qualities (maybe they get a bigger cut from the company) and most obviously (3) assuming that the sample is representative of all dermatologists (notice it just says "survey", it doesn't tell us whether it was a good survey at all).
Raziel's got a killer breakdown of some of the flaws running around in this argument.
However, I have to agree with
Alvanith that the conclusion here is not that Dermactin is the best, but rather that "if you need a skin cream, use Dermactin". The difference there is subtle, but significant.
Alvanith Wrote:P.S. I am not sure whether the advertiser is assuming the dermatologists surveyed prefer Dermactin for its desirable qualities. Maybe the advertiser is implying to the consumers that the dermatologists' preference is based on the quality of the product, but the advertiser may not necessarily believe his recommendation is based on the dermatologists' preference for the quality. Does implying necessarily mean assuming? The advertiser here is just recommending the product because of the 75% approval from demonologists surveyed. Am I overthinking here? Somebody please help me! Thanks in advance:)
I understand what you're saying here, because we're pretty skeptical of this smarmy advertising guy as a general matter. In fact, if we met this guy in real life, we'ld probably be pretty skeptical of whether he even believes his own conclusion.
But we can't dismiss an assumption on the LSAT because we think the author is just lying about the conclusion - that way lies madness. We have to assess what the author would have to be assuming in order to
claim their conclusion in good faith.So, let's try negating this concept - if the dermatologists "preferred" Dermactin based on something other than its quality or functionality (say, based on it's fun sounding name!), then this would destroy the potential usefulness of this evidence in supporting the conclusion that you should use Dermactin! This totally destroys the argument being put forward.
In other words, what you are characterizing as 'implying' is really what you see as the author (advertiser) hoping his *listeners* assume from this statements. In this scenario, the advertiser doesn't believe his own conclusion - but he does hope his listeners will.
All in all it's less mind-bending to just assume that authors are making arguments in good faith, and that when they are wrong they are flawed rather than lying. 'Never attribute to malice that which is adequately explained by stupidity' is a good mantra for the LSAT.
Let me know if that helps a bit!