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Topic: compare two methods for measuring concentration
Replies: 4   Last Post: Jul 17, 2012 5:05 PM

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Bruce Weaver

Posts: 735
Registered: 12/18/04
Re: compare two methods for measuring concentration
Posted: Jul 17, 2012 7:23 AM
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On 16/07/2012 10:10 AM, davidarteta2011@gmail.com wrote:
> Hi, I have an experiment where I have a gold-standard method to calculate the concentration of a sample and two methods I want to test how well they measure the concentration and if one of them is better than the other. I have set up a concentration gradient from 0 to 5 units in breaks of 0.5 and measure each sample with each new method.
> I have done an ANOVA test on the measurements obtained for each method and have found that measurements are statisticaly different between the two methods.
> Then I have run a linear regression on each method to see how each method fits the gradient, and I see that one of the two methods has a higher R-squared value.
> My question is, can I say based on R or R-square values that one of the methods is significantly better than the other at measuring concentration based on both the R-square value and the significance of the ANOVA test?
>
> Thanks,
>
> Dave
>


The method due to Altman & Bland could be used for comparing each of the
methods to the gold standard.

http://www-users.york.ac.uk/~mb55/meas/ba.htm

HTH.

--
Bruce Weaver
bweaver@lakeheadu.ca
http://sites.google.com/a/lakeheadu.ca/bweaver/Home
"When all else fails, RTFM."





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