LSAT PrepTest 44 Section 2 Question 17 Explanation | Logical Reasoning

I didn't write the following blog post. It was already on the blog when I took over the URL. The following blog post may contain mistakes. -Steve

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This Logical Reasoning question is from the October 2004 LSAT.

The stimulus provides a set of figures, the percentage of the bird's weight that its egg represents, for several different types of birds, and the figures differ significantly. The idea is the ratio of the egg's weight to the bird's weight, not the absolute weight of the egg of bird. It's a comparison.

Given that, we should pre-phrase an answer, like we did on Question 1, our most recent Logical Reasoning question. This helps us find the right answer more quickly and not get bogged down in wrong ones. What "proposition" does the argument illustrate? Well, considering the evidence, maybe it illustrates something like "the egg weight to body weight ratios are smaller among bigger birds."

Looking at our answer choices using our pre-phrase, we see that it fits C well. Since this is practice, let's go through the other 4 answers so we know why they're wrong.

A) The argument says nothing about comparing the weight of eggs to their volume. This out of the scope of the argument. It might be true, but the argument says nothing about it.

B) This is wrong because it's saying that lighter birds lay heavier eggs. The argument says just the opposite, that the heavier birds like the goose and ostrich are much heavier than those of the light hummingbird.

C) Correct.

D) The argument doesn't support this; this is the opposite of what the argument is saying. The argument says that geese and ostriches, which are much larger than hummingbirds, also have much larger eggs, so there is a correlation between egg size and adult bird size.

E) This is beyond the scope of the argument. It says nothing about birds varying more in egg size and in body weight. It says only that they do vary in both those quantities. It doesn't say if one varies more than the other. So, it cannot be the "proposition" the argument illustrates.

Remember:

1) As in Question 1, keep a look out for answer choices that are the opposite of what the passage is saying or are out of the scope of the passage, especially in Logical Reasoning sections. However, this is helpful in Reading Comprehension too.

2) Pre-phrase an answer based on your analysis of the question before you even look at the answer choices. That way, you'll know the right answer your looking for. Time is a big factor for most LSAT-takers...they don't have enough of it. Pre-phrasing can let you answer questions more quickly.