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#17 - On average, city bus drivers who are using the new

LSAT Master
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I got the question right.

I was just curious of expression such as "generally" and "on average."

When I was studying LR bible, there were some words that were meant to be "some," and "most."

For example, "usually," and "typically" are categorized under "most."

Is "generally" under "most"?

Also, is "generally" meant to imply situations being more frequently held than "on average"?
Ron Gore
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That's a great question, Reop.

The word "generally" implies the group as a whole, though taking into consideration that there may be exceptions not covered by the sweeping description. So, in answer choice (E) to the question you reference, the second sentence could be understood: "as a whole, ignoring any exceptions, lawn mowers powered by electricity require less maintenance than do lawn mowers powered by gasoline." However, don't confuse this term with "all" which precludes the possibility of exception. You can think of it as "most." To cross-reference the conversation with our Logical Reasoning Bible, the list on page 308 of the January 2013 version includes the word "typically," which is synonymous with "generally."

The word "average," used in both the stimulus and the correct answer choice, (C), has a very different context than "generally," and expresses a specific numerical relationship among numbers. Because the average is, to quote Merriam-Webster, "a single value (as a mean, mode, or median) that summarizes or represents the general significance of a set of unequal values " you have to be cautious of conflating that result with the idea of "most."

In the stimulus to the question you referenced, there were bus drivers using the old system, and bus drivers using the old system. To simply discuss the difference between "most" and "average," consider this example.

You have five drivers using the old system and five drivers using the new system. On a scale of 1 to 10, with 10 being the best time record possible, let's say the results are:

Old: 5, 5, 5, 5, 5

New: 10, 9, 4, 4, 4

Although most of the drivers using the new system had a worse time record than any of the drivers under the old system, the average record of drivers under the new system was higher (6.2) than the average record of those under the old system (5).

Hope that helps sort out the meanings.

LSAT Master
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Thank you so much for the details! It helped me a lot!
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Hello PS,

I read through the stimulus and thought that the flaw was a simple Mistaken Reversal. My reasoning is as follows:

P: Use new fare collection system ---------> better on time record
C: M has best on time record --------> using computerized fare collection system

I attacked the answer choices based on this and immediately saw A as having a mistaken reversal as well:

P: Acquired after 1998 -----> large capacity
C: Vehicle has largest capacity ------> acquired after 1998

I answered A confidently and moved on, only to see that the correct answer is C. May I please have an explanation on my logic and the mistakes I made?

Really appreciate it!
Brook Miscoski
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The reason that you can't simply look for a Mistaken Reversal is that the stimulus is not based on conditional reasoning. Instead, from our common errors of reasoning list, it is most like an error of composition.

The stimulus establishes the average characteristic is that drivers using the new computerized systems have better on-time records, but that does not mean that characteristic is found in each member of the group (after all, it's an average). That is why (C), and not (A), is correct.

If you did approach this as a Mistaken Reversal, you could still get it right by making sure the concept of "average" is preserved. Because (A) is absolute ("all"), it cannot reflect all of the logical elements of the stimulus. That's another reason to review all of the answer choices before moving along.