PT44 S2 Q17 The tiny hummingbird weighs little

[aileenann]

This question is a principle question in disguise - they give us facts and then ask us to find a general rule that fits it. We need to be especially careful about scope issues here - we don't want to overstep our facts in choosing an answer choice.

The facts we know here are:

egg = 15% of adult body weight
goose egg is bigger than h. egg, but only 4% of goose adult body
ostrich egg even larger, but only 1.6%

We won't be able to say anything about the absolute size of the eggs (we'd have to use our outside knowledge that an ostrich, for example, is more than 15 times the size of a hummingbird). So the only thing we know is that percent of body weight that egg is seems to decline as the bird's body size gets bigger. This fits (C) perfectly. There is really nothing else that could be concluded from these fact patterns.

Let's see what's wrong with the incorrect answer choices, to see which kinds of incorrect answer choices they have given us:

(A) has a degree problem - it's hard to know what "vary widely" means - that is the sort of relative judgment we'd have to have more context to make. You don't want to choose an answer choice with a fuzzy meaning like this if you can avoid it

(B) is probably the most tempting wrong answer. But remember, we only know about %'s - we don't know about the actual size of eggs.

(D) has the same problems as (A) and (B) - we don't know the size and we don't know what it means to vary greatly.

(E) We don't know anything about the sizes of the birds as far as just how much they vary, so this also goes out of scope.

Any questions or additional thoughts on this one?