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# monte carlo result on std dev and sigma

Last post Thu, Jan 3 2013 9:29 AM by surreyian. 4 replies.
 Started by surreyian 03 Jan 2013 07:53 AM. Topic has 4 replies and 957 views
• #### Thu, Jan 3 2013 7:53 AM

• surreyian
• Joined on Tue, May 17 2011
• Posts 19
• Points 320
monte carlo result on std dev and sigma
 Hello,What is the differenence between sigma and std dev in monte carlo simulation. There two reading are not exactly the same, so what is the difference?
• Post Points: 20
• #### Thu, Jan 3 2013 8:07 AM

Re: monte carlo result on std dev and sigma
 Where are you looking at them? Which version? I just want to make sure I tell you the precise answer... Andrew.
• Post Points: 20
• #### Thu, Jan 3 2013 8:17 AM

• surreyian
• Joined on Tue, May 17 2011
• Posts 19
• Points 320
Re: monte carlo result on std dev and sigma
• Post Points: 20
• #### Thu, Jan 3 2013 8:48 AM

Re: monte carlo result on std dev and sigma
 sigma on the Yield tab is the sample standard deviation (which is the same as the "sd" annotated on the histograms), whereas std dev on the Summary tab is the population standard deviation.I'm sure you remember the difference from school maths, but if not, it's covered on http://en.wikipedia.org/wiki/Standard_deviationGiven that you are using a sample of the points, the sample standard deviation is the one you normally want. With a sufficiently large number of samples, the difference is small (because the sample uses a denominator of N-1 and population uses a denominator of N, so if N was 1000, it would be roughly 0.1% different).Regards, Andrew.
• Post Points: 20
• #### Thu, Jan 3 2013 9:29 AM

• surreyian
• Joined on Tue, May 17 2011
• Posts 19
• Points 320
Re: monte carlo result on std dev and sigma
 that makes sense now. thanks andrew
• Post Points: 5