Q19

[lcleme02]

Hi! When I first did this question I made two T-charts where H and L were selected -- but with different distributions of animals.

In one scenario (2-1-3) I had G,H,L,T,V,Z in and F,NK out. In the second scenario (2-2-2) I had G,H,L,N,V,Z in and F,K,T out.

Answer choice B said that T is selected -- which was true in my first frame, so seeing as it was a could be true question - I chose B. But I see now that the correct answer was C, that Z is selected -- is this because it was true in both frames? Does an answer to a could-be-true question have to be true in both scenarios?

Any insight would be greatly appreciated!

[christine.defenbaugh]

Thanks for posting, lcleme02!

I'm a bit confused by your frames for this question. Couldn't there be only one monkey, giving us perhaps a 1-3-2 scenario? But before we get to the numerical distribution,, we really need to carefully play out the conditional information that we have.

So, if we have both H and L, what do we know? Rule #1 tells us that F has to be out (and I see you have that in both frames). But Rule #3 also tells us that if we select H, we then have to select K. K is out in both your frames, but it should be IN! Rule #4 then tells us that if we select K, we must select N - so N must be IN in both frames also! Finally, rule #2 tells me that once we have N, we can't select T!

So, before we even think about frames, we have this lineup:
IN .......................................OUT
H / K L N / ? ....................F / - / T

We've placed everyone except for G, V, and Z - two of those are going in, and one of them is going out. We could make frames from here (three frames: G out, V out, and Z out), but there's not much point. Let's just knock of the four rule violators.

(A) F can't be selected! Rule #1 says H and F can't be selected together!

(B) T can't be selected! If H, then K, and if K, then N, and N and T can't be selected together. T is always out!

(D) & (E) We have to have K, L, and N, so there are exactly three pandas selected, not one or two!

Be very careful to completely follow the inference chain on a conditional question!

Now, to answer your larger question - if you have two frames, and something is true in just one of your frames, that's absolutely a valid answer for a "could be true" question. For something to be a "must be true" it would have to be true in ALL the frames. Similarly, for something to be a 'rule violator', or a "must be false", it would have to be false (or violate rules) in ALL the frames. Your instincts about that were spot on, you just had incorrect frames you were working with!

Please let me know if this helps to answer your question!