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shyind
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A researcher collected n readings from a scientific experiment. Is the
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11 Nov 2015, 01:14
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39% (01:21) correct 61% (01:18) wrong based on 124 sessions

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A researcher collected n readings from a scientific experiment. Is the standard deviation of the measurements less than 5?

(1) The mean of the positive difference between each measurement and the mean is 5.

(2) The variance of the set of n measurements is 25.
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HardWorkBeatsAll
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A researcher collected n readings from a scientific experiment. Is the
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16 Nov 2015, 00:54
(1) is insufficient - SD involves the mean of squared differences. Mean of squared differences can't be found from mean of differences. Hence, SD cannot be found.

(2) is sufficient - variance is just the square of the SD. Since we take the positive value of sq. root for calculating SD, we can say it is 5. This is not less than 5 and answers the question asked.

Hence, (B).

shyind
A researcher collected n readings from a scientific experiment. Is the standard deviation of the measurements less than 5?

(1) The mean of the positive difference between each measurement and the mean is 5.

(2) The variance of the set of n measurements is 25.
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GMAT 1: 800 Q51 V49
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Posts: 21,775
A researcher collected n readings from a scientific experiment. Is the
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19 Nov 2015, 18:01
Hi shyind,

What is the source of this question? I ask because the GMAT Quant section is not going to test you on the concept of 'variance.' As such, this question isn't realistic. There are plenty of quality GMAT study materials on the market, so you might want to spend your time with any of those resources and not a source that is questionable.

GMAT assassins aren't born, they're made,
Rich
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A researcher collected n readings from a scientific experiment. Is the
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11 Dec 2022, 07:28
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.

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