All Labrador retrievers bark a great deal. All Saint Bernards bark infrequently. Each of Rosa’s dogs is a cross between a Labrador retriever and a Saint Bernard. Therefore, Rosa’s dogs are moderate barkers.
Which one of the following uses flawed reasoning that most closely resembles the flawed reasoning used in the argument above?
(A) All students who study diligently make good grades. But some students who do not study diligently also make good grades. Jane studies somewhat diligently. Therefore, Jane makes somewhat good grades.
(B) All type A chemicals are extremely toxic to human beings. All type B chemicals are nontoxic to human beings. This household cleaner is a mixture of a type A chemical and a type B chemical. Therefore, this household cleaner is moderately toxic.
(C) All students at Hanson School live in Green County. All students at Edwards School live in Winn County. Members of the Perry family attend both Hanson and Edwards. Therefore, some members of the Perry family live in Green County and some live in Winn County.
(D) All transcriptionists know shorthand. All engineers know calculus. Bob has worked both as a transcriptionist and as an engineer. Therefore, Bob knows both shorthand and calculus.
(E) All of Kenisha’s dresses are very well made. All of Connie’s dresses are very badly made. Half of the dresses in this closet are very well made, and half of them are very badly made. Therefore, half of the dresses in this closet are Kenisha’s and half of them are Connie’s.
A. Tempting, but flawed. This choice uses a "some" statement and fails to clearly connect a lack of diligence to very poor grades. A more fitting version would clearly state: diligence = good grades, no diligence = bad grades, so partial diligence = somewhat good grades.
B. Correct. This is a precise match to the reasoning in the stimulus. If we treat Type A as a Labrador and Type B as a Saint Bernard, and "toxicity" as barking, it mirrors the original structure: each dog is a mix of both breeds, and thus each barks halfway.
C. Not quite. The stimulus involved a mix within a single entity—each dog was a 50/50 mix. This option wrongly implies that different people (or family members) live in different counties. To be parallel, it should say each Perry family member lives half in Green County and half in Winn County.
D. Close, but still off. To parallel the original, it should say something like: “Transcriptionists only write shorthand, engineers only write calculus. Bob writes both shorthand and calculus.” That would mirror the mixed nature seen in the original argument.
E. Similar to C, this one misses the key point of combination. The original argument dealt with a blend of characteristics within a single item. This option doesn’t combine traits in one dress—it keeps them separate—so it doesn't reflect the logic used in the stimulus.
