On average, city bus drivers who are using the new computerized fare collection system have a much better on time rec...

Ravi February 18, 2019

@Steph,

Happy to help.

The stimulus is saying that on average, city bus drivers who are using
the new computerized fare system are more punctual than are ones who
are using the old collection system. Millicent Smith is the most
punctual city bus driver, so the argument concludes she has to be
using the computerized fare system.

See the flaw? This is a whole-to-part flaw. On average, sure, the bus
drivers using the computerized system are more timely; however, this
does not mean that every single city bus driver with above average
punctuality uses the computerized fare system. There could be an
outlier bus driver using the old fare system who is more timely than
all of the bus drivers who use the computerized fare system, so this
argument contains the whole-to-part flaw.

The question asks, "Which one of the following contains flawed
reasoning most similar to that contained in the argument above?"

We know that the stimulus has a whole-to-part flaw, so we just need to
find an answer choice that also has a whole-to-part flaw in it.

(A) says, "All the city’s solid waste collection vehicles acquired
after 1988 have a larger capacity than any of those acquired before
1988. This vehicle has the largest capacity of any the city owns, so
it must have been acquired after 1988."

This argument is really close to being valid. If the city bought a
vehicle after '88, then it's bigger than every vehicle prior to '88.
We also know that any single vehicle bought after '88 is larger than
any vehicle before '88, we know the largest vehicle can't come from
'88. However, the largest vehicle could be from the year '88 itself
since the premise gives us no information about '88. This argument
doesn't exhibit the whole-to-part flaw of the stimulus, so we can get
rid of it.

(B) says, "The soccer players on the blue team are generally taller
than the players on the gold team. Since Henri is a member of the blue
team, he is undoubtedly taller than most of the members of the gold
team."

This is a tricky answer choice, but it doesn't match up to the
stimulus because the stimulus tells us that Millicent has a certain
characteristic (being the most on-time) and concludes from that that
she is a member of the group using the new computerized fare system
because that group on average is more timely. (B), however, makes a
flaw in the reverse (part-to-whole) direction, as it says that Henri
is a member of a particular group (the blue team) and concludes that
he has a trait (taller than most of the members of the gold team).
Because the flaw is done in the reverse direction, we can get rid of
(B).

(C) says, "This tomato is the largest of this year’s crop. Since the
tomatoes in the experimental plot are on average larger than those
grown in the regular plots, this tomato must have been grown in the
experimental plot."

The flaw in (C) matches our stimulus flaw (whole to part) really well.
It says that one particular tomato is the largest and says that since
the experimental plot has tomatoes that are on average larger than
those in the regular plots, this tomato must be from the experimental
plot. This is the same type of flaw (whole to part) that we found in
the stimulus, and it's the correct answer. Unlike (B), the flaw in (C)
goes in the right direction.

(D) says, "Last week’s snowstorm in Toronto was probably an average
storm for the area. It was certainly heavier than any snowstorm known
to have occurred in Miami, but any average snowstorm in Toronto leaves
more snow than ever falls in Miami."

This argument is different from the type of argument we saw in the
stimulus because it attempts to conclude that last week's snowstorm
was average instead of attempting to place the snowstorm into part of
a larger group of snowstorms, which is the type of flaw (whole to
part) that the stimulus does. As a result, we can get rid of (D).

(E) says, "Lawn mowers powered by electricity generally require less
maintenance than do lawn mowers powered by gasoline. This lawn mower
is powered by gasoline, so it will probably require a lot of
maintenance."

The problem with (E) is that it switches gears from comparing the
maintenance between two types of mowers to making an absolute claim
about gas mowers needing lots of maintenance. This is not the whole to
part flaw found in the stimulus, so we can get rid of this choice.

Does this make sense? Let us know if you have any questions!