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In a certain experiment, the data collected is the number of organisms
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21 Sep 2021, 01:14
21 Sep 2021, 01:14
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In a certain experiment, the data collected is the number of organisms per sample, and this data follows a normal distribution. If the sample of data has a mean of 60 and a standard deviation of 12, which of the following is exactly 1.75 standard deviations more than the mean?
a) 48
b) 60
c) 72
d) 77.5
e) 81
a) 48
b) 60
c) 72
d) 77.5
e) 81
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: In a certain experiment, the data collected is the number of organisms
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21 Sep 2021, 06:09
21 Sep 2021, 06:09
Carcass wrote:
In a certain experiment, the data collected is the number of organisms per sample, and this data follows a normal distribution. If the sample of data has a mean of 60 and a standard deviation of 12, which of the following is exactly 1.75 standard deviations more than the mean?
a) 48
b) 60
c) 72
d) 77.5
e) 81
a) 48
b) 60
c) 72
d) 77.5
e) 81
--------ASIDE--------------------------------------
A little extra background on standard deviations above and below the mean
If, for example, a set has a standard deviation of 4, then:
1 standard deviation = 4
2 standard deviations = 8
3 standard deviations = 12
1.5 standard deviations = 6
0.25 standard deviations = 1
etc
So, if the mean of a set is 9, and the standard deviation is 4, then:
2 standard deviations ABOVE the mean = 17 [since 9 + 2(4) = 17]
1.5 standard deviations BELOW the mean = 3 [since 9 - 1.5(4) = 3]
3 standard deviations ABOVE the mean = 21 [since 9 + 3(4) = 21]
etc.
----NOW ONTO THE QUESTION!!!!-----------------------------
1.75 standard deviations more than (aka ABOVE) the mean = 60 + (1.75)(12)
= 60 + 21
= 81
= E
Cheers,
Brent
gmatclubot
Re: In a certain experiment, the data collected is the number of organisms [#permalink]
21 Sep 2021, 06:09
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