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Critical Reasoning: Investigation Questions

John usually sorts incoming mail, such as bills and legal papers, into different folders according to various criteria. When he needs a specific document, John looks for it in the appropriate folder. However, if John mistakenly puts a letter into the wrong folder, he will not find it later when he looks in the appropriate folder. Jane hypothesizes that refraining from sorting the letters, but rather searching through all of them when necessary, would be more efficient.

Which of the following investigations is most likely to yield significant information that would help evaluate Jane's hypothesis?

Incorrect.

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This answer choice suggests an investigation that will allow us too see whether John likes the new system better. However, knowing if John would be happy would not really help us discover if the second system is more efficient than the first, which is the task at hand.

Incorrect.

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This answer choice suggests a comparison between the number of sorting errors in each method over a month. However, since there is no sorting involved in the second system (and therefore no sorting errors), this may inaccurately portray it as a more effective system.

The truth of the matter is that even though the second system has no sorting errors, merely going all over the letters may take longer than it would to have a sorting error every now and then.

Incorrect.

[[snippet]]

This answer choice suggests a comparison between two factors of the first system - sorting time and look-up time in case there is an error - instead of comparing factors of both systems. Since nothing about the second system is discussed we cannot determine which system is more efficient.

Incorrect.

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This answer choice illogically compares two identical things. Looking up a letter without having previously sorted it practically means going though all the letters. Looking up a letter in case John cannot find it in its designated folder also means going through all the letters in all the folders. Therefore, this test will not give us any relevant or new information.

Great!

[[snippet]]

This answer choice suggests we compare the advantages and disadvantages of John's method over Jane's suggestion. John saves time by having pre-sorted letters, but he also wastes time on sorting the letters and an occasional sorting error.

If the time saved by having pre-sorted letters is greater (>) than the time wasted on sorting them and on an occasional sorting error, then John's system is more efficient than Jane's.

However, if the opposite is true and the time wasted on sorting mail and on misplaced letters is greater (>) than the time saved by having organized folders, then John's system is less efficient as Jane claims.

Either way, comparing the advantages and disadvantages is the correct investigation which would help us evaluate Jane's hypothesis.

Stopping the sorting, and seeing whether John is pleased with the new system
Using each method for a month, and seeing which has more sorting errors
Comparing the time it takes to sort the letters with the time it takes to find a misplaced letter
Comparing the look-up time without sorting with the look-up time in case of a sorting error
Comparing the time saved by having pre-sorted folders to the time wasted on sorting and on sorting errors