valid inferences. Help greatly appreciated!

Comments

• 1 Like

  runiggyrun Alum Inactive Sage Inactive ⭐

  January 2016 2481 karma

  1. You can't draw any inference about any sedans being red, and Manhattan are not saying that you can. They say you can draw the inference that some things are red. Which is true, assuming cars are things.
  2. Again, you can't make any inference about any children playing both, and they don't say you can. They say " some people who play sports are children" which is absolutely correct assuming children are people.
  The assumptions required are very small and solidly common sense, so I don't think they need to be spelled out for the drill
• 1 Like

  beth.flanders Alum Member

  January 2016 edited January 2016 212 karma

  The inferences (MBT) that Manhattan are making are correct. They are just reiterating one of the statements using different words and not combining the two statements to make a inferences. So in your first example:

  @"mc_meatt" said:
  1. Some cars are sedans, and some cars are red.
  

  Manhattan indicates "Some things that are red are cars." would be correct because a car is a 'thing.'
  
  Similarly in the second example:

  @"mc_meatt" said:
  2. Most children play sports, and some children play instruments.
  

  
  to infer that "Some people who play sports are children." is also correct because children are people.
  
  In both examples, one could also infer "At least one thing that is red is a car" or "At least one person who play sports is a child" You could also have inferred the negation of one of the statements such as "Most cars are NOT sedans." and that would be a correct inference as well.
  
  You are correct in that we would not be able to make valid inferences combining the statements together. However, that would be a good MBF question or trap answer choice testing us on making invalid inferences.
• nye8870 Alum ⭐

  January 2016 1749 karma

  I'm glad I studied 7sage not Manhattan
• GSU Hopeful Core ⭐

  January 2016 1644 karma

  @nye8870 said:
  I'm glad I studied 7sage not Manhattan
  
  
  
  
  
  
  
  

  That's an understatement.
• disasterpiecev Free Trial Member

  January 2016 29 karma

  @Beth. Could you properly infer that most cars are not sedans? "Some" can include "most" right (if 99/100 cars are sedans, then "some cars are sedans" and it wouldn't be proper to infer that "most cars are not sedans")? Or am I misunderstanding? Thanks.
• beth.flanders Alum Member

  January 2016 212 karma

  @nye8870 and @"GSU Hopeful" I completely agree, 7Sage is soooo much better!
  
  @disasterpiecev, you are correct and thank you for correcting me. We cannot properly infer Most cars are not Sedans. I had "few" (3-4) on my mind which implies some are, most are not. So @mc_meatt, please disregard that portion of the explanation and sorry for the confusion.