Further Inference

    • July 22, 2016 at 3:01 pm #2287

      Hey all –

      I’m going through the first “Full Setup” logic game drills that begin on page 153. On the first game setup (“A recruiter will interview six candidates…”), I am confused about whether an extra inference can be made that is not noted in the answer key.

      Here is a truncated version of the game:

      Elements: M, N, O, P, Q, and R (one at a time and in order)
      Two candidates are experienced, the rest are inexperienced.
      Rules: Neither of the first two candidates interviewed is experienced.
      Either M or N, but not both, is experienced.
      P interviews before both O and R.
      R does not have experience.

      Here is the order of elements I came up with: Pi Ri _ _ _ _ (Whereas the solution is: i i _ _ _ _

      I figured that if P must come before both O and Ri, Ri cannot be in the first position (as P could not come before it). Therefore, Ri must come in the second position and Pi in the first.

      Thanks for the help – I am noticing that I make at least a couple erroneous inferences per set, so I wanted to make sure I wasn’t making one in this case.

    • July 22, 2016 at 3:35 pm #2289
      Mike Kim

      Hey Timothy —

      Hope the studying is going well —

      Not to sound like a stalker or anything, but I have to mention that I also happen to be a huge fan of both the Truman Show and East of Eden —

      You should definitely expect to see certain inferences that I don’t notate, and vice-versa —

      In terms of this particular inference, however, I think you ran into trouble when you assumed that P and R must go in the first two positions — we don’t know that for sure, and that’s why we can’t make that inference.

      Some guesses as to where things went wrong for u:

      1) Perhaps you misread the rule that 2 are experienced and 4 inexperienced or
      2) Perhaps it just slipped your mind that there are other (unmarked) “i” slots on the board.

      If it’s #2, one thing I suggest you consider really focusing on in your diagramming and mindset is being very, very careful about separating out what could be true vs what must be true — as I’ll discuss a lot more later in the Trainer, must be vs could be is the essential divide between right and wrong answers (it’s also one of the toughest things for us to keep organized in our minds ) so, as you diagram and make inferences, you always want to questioning and considering whether the inferences represent possibilities or absolutes.

      Not sure if the above is relevant to your situation, but it’s something I feel is very important so I thought it was worth mentioning —

      In any case, hth, and if you have any follow-up just let me know — MK

    • July 22, 2016 at 3:42 pm #2290

      You are correct to infer that R cannot be in the first position 🙂 If there were only three total candidates [P, O, R], and P must come before both O and R, then yes P would have to go first, with O going either second or third and R going either second or third.

      However, there are six total candidates, so while P could go first, it doesn’t have to. Since there are two candidates that must come after P, and no candidates must come before P, this means that the earliest P can go is first, and the latest it can go is fourth.

      Hope that helps 🙂

    • July 22, 2016 at 3:51 pm #2291

      ooops, sorry, didn’t see that Mike already provided an excellent explanation 🙂

    • July 22, 2016 at 3:54 pm #2292
      Mike Kim

      Ha – I think we answered simultaneously — actually went back and cleared up something in mine after I read yours, so definitely great (as always) to have u chime in! — MK

    • July 22, 2016 at 3:57 pm #2293

      Ah – of course! I totally misread the inexperienced/experienced rule. I swapped in my mind 2 experienced for 2 inexperienced. Of course, if there were only two inexperienced, then my inference would be correct – but it’s not! Thanks for the reminder to pay closer attention to all my diagramming.

      dannypearlberg also brings up another question I have: Is it worthwhile to notate inferences about where elements cannot go? I find this most often in x before y scenarios. For example: There are three elements, A, B, and C in order. B comes before A. Is it worthwhile in this scenario to notate that first position cannot be A, or would that be superfluous/confusing in the long run?

      Thanks for the help! Much appreciated that you’re taking time on a Friday afternoon.

    • July 22, 2016 at 3:59 pm #2294

      Definitely worthwhile to notate inferences about where elements cannot go 🙂

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