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# Standard Deviation List question

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Intern
Joined: 13 Apr 2013
Posts: 22

Kudos [?]: 3 [0], given: 3

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30 Jun 2013, 09:37
Hi,

Can you tell me how I would solve a question similar to the following?

Let's say I have the following list representing scores on an exam for 3 students

student: a b c
test 1: 4 5 6
test 2: 7 5 9
test 3: 4 2 1

how can I find which student had the biggest standard dev and the smallest?

I know this is very simple but I'm just confused when the list is a lot bigger what the quickest way would be.

Thanks!

Kudos [?]: 3 [0], given: 3

Math Expert
Joined: 02 Sep 2009
Posts: 42257

Kudos [?]: 132702 [0], given: 12335

Re: Standard Deviation List question [#permalink]

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30 Jun 2013, 10:18
mokura wrote:
Hi,

Can you tell me how I would solve a question similar to the following?

Let's say I have the following list representing scores on an exam for 3 students

student: a b c
test 1: 4 5 6
test 2: 7 5 9
test 3: 4 2 1

how can I find which student had the biggest standard dev and the smallest?

I know this is very simple but I'm just confused when the list is a lot bigger what the quickest way would be.

Thanks!

The standard deviation of a set shows how much variation there is from the mean, how widespread a given set is. So, a low standard deviation indicates that the data points tend to be very close to the mean, whereas high standard deviation indicates that the data are spread out over a large range of values.

Back to the question.
Scores of Student A {4, 7, 4} = {4, 4, 7}
Scores of Student B {5, 5, 2} = {5, 5, 2}
Scores of Student C {6, 9, 1}

Sets A and B are equally widespread, thus they will have the same SD. Set C is more widespread than these two so it will have the greatest SD.

Theory on Statistics and Sets: math-standard-deviation-87905.html

DS questions on Statistics and Sets to practice: search.php?search_id=tag&tag_id=34
PS questions on Statistics and Sets to practice: search.php?search_id=tag&tag_id=55

Hope it helps.
_________________

Kudos [?]: 132702 [0], given: 12335

Re: Standard Deviation List question   [#permalink] 30 Jun 2013, 10:18
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