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27 Jun 2008, 01:49
Kudos
Bookmarks
Hi there guys,
Could some one help me out, what exactly is standard deviation and range, what do these terms mean?
Could some one help me out, what exactly is standard deviation and range, what do these terms mean?
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
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27 Jun 2008, 10:18
Kudos
Bookmarks
Range : The difference between minimum and maximum values
For example if a set has got ; 10,20, 30, 40 and 50. The range is 50- 10 = 40
Standard Deviation : It is little more complex than Range. I assume you know what is mean as you did not ask about it.
Going with the same example
10,20, 30, 40 and 50. The mean is 30
Now we need to calculate the difference from mean for each of the elements
10 -30 = -20
20 -30 = -10
30 -30 = 0
40-30 = 10
50-30 = 20
Now compute the squares of these differences and sum them up
400 + 100 + 0 + 400 + 100 =1000
Now calculate the average of this difference
1000/5 = 200
Now calculate square root of 200 = 14.1421
This is the Standard Deviation.
Usually we will never be asked to calculate SD in GMAT the questions will be around the way computation is done. If we know how we are going to arrive at SD, it will be easy to answer those.
Hope this helps
For example if a set has got ; 10,20, 30, 40 and 50. The range is 50- 10 = 40
Standard Deviation : It is little more complex than Range. I assume you know what is mean as you did not ask about it.
Going with the same example
10,20, 30, 40 and 50. The mean is 30
Now we need to calculate the difference from mean for each of the elements
10 -30 = -20
20 -30 = -10
30 -30 = 0
40-30 = 10
50-30 = 20
Now compute the squares of these differences and sum them up
400 + 100 + 0 + 400 + 100 =1000
Now calculate the average of this difference
1000/5 = 200
Now calculate square root of 200 = 14.1421
This is the Standard Deviation.
Usually we will never be asked to calculate SD in GMAT the questions will be around the way computation is done. If we know how we are going to arrive at SD, it will be easy to answer those.
Hope this helps
06 Jul 2008, 00:45
Kudos
Bookmarks
thanks a lot for your explanation, just what I needed. :-D
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
