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# The reaction time of 1000 Rhesus monkeys was measured. The

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The reaction time of 1000 Rhesus monkeys was measured. The [#permalink]  16 Oct 2017, 08:36
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Question Stats:

33% (00:01) correct 66% (00:40) wrong based on 3 sessions
The reaction time of 1000 Rhesus monkeys was measured. The average time it took the monkeys to respond to a quickly moving object in their visual fields was .135 seconds, with a standard deviation of .021 seconds (assume a normal distribution). If one of the geriatric monkeys had a reaction time of .205 seconds, then that monkey’s reaction time is how many standard deviations from the mean?

A. 0 – 1 standard deviations
B. 1 – 2 standard deviations
C. 2 – 3 standard deviations
D. 3 – 4 standard deviations
E. 4 – 5 standard deviations

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[Reveal] Spoiler: OA
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Re: The reaction time of 1000 Rhesus monkeys was measured. The [#permalink]  16 Oct 2017, 09:48
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The mean is .135 while the time we need to analyze is .205. Given a sd of 0.021, we can compute how many sd there are between the time of .205 and the mean using $$\frac{.205-.135}{0.21} = 3.33$$.

Thus, the time is between 3 and 4 sd above the mean. Answer D
Re: The reaction time of 1000 Rhesus monkeys was measured. The   [#permalink] 16 Oct 2017, 09:48
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