Land Surveyor needs help

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Land Surveyor needs help
Message posted by Carl (via 172.159.75.60) on December 19, 2001 at 12:18 AM (ET)

I was searching the Web for an answer to a statistical problem I have and I found this web site. I hope you can help me. Heres the problem:

I am a surveyor and am comparing the accuracy of two survey instruments. One states an accuracy of 2mm Standard Deviation and the other 3mm MSE(mean squared error). How does the MSE value compare to the standard dev. value and which in your opinion is more accurate? I have a feeling the MSE value is misleading but could be wrong. Most manufactures state the Standard deviation and Im curious as to why this particular manufacturer uses MSE. I have wrote the manufacturer directly and requested the Standard Deviation and was informed that they do not have the Standard Dev and use MSE because it is a more accurate method. Is this true?

I thank you for your time.

Carl Ursel
cursel@hotmail.com

READERS RESPOND:
(In chronological order. Most recent at the bottom.)

Re: Land Surveyor needs help
Message posted by JG (via 128.8.22.87) on December 19, 2001 at 4:32 AM (ET)

MSE and standard deviation are the same thing. The only possible difference is that population standard deviation is MSE and sample standard deviation is
square root(n/(n-1))*MSE,where n is sample size. Sample standard deviation really means the population standard deviation as estimated from sample data.

Re: Land Surveyor needs help
Message posted by mbd (via 152.163.195.177) on December 19, 2001 at 8:09 PM (ET)

In my experience, the standard deviation is the square root of the MSE. In the end, you have to ask the vendor what he/she means by MSE.

Re: Land Surveyor needs help
Message posted by JG (via 128.8.23.67) on December 20, 2001 at 1:28 AM (ET)

MSE is mean squared error. For populations sd is square root of MSE and for samples sd is
square root of {(n-1)/n)*MSE where n is sample size and sd is the sample standard deviation or the estimate of the population standard deviation using sample date. This is a correction to my previous post.

Re: Land Surveyor needs help
Message posted by JG (via 128.8.23.67) on December 20, 2001 at 1:36 AM (ET)

If the manufacturer says MSE is 3 mm then he must be talking about square root of MSE. This is what coused me to confuse MSE with square root of MSE in my original comments.

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