Thread: Relative standard deviation vs t-test

Hi Guys, hope you can help!

I'm doing some chemistry analysis in which I run 6 replicate injections of my standard preparation, followed by my sample injections. However, in order to ensure the system is running ok, I run 2 injections of the same standard prep after every 6 sample injections.
Am I right in thinking the best (only?) way of comparing the initial 6 standard injections with the first 2 system suitability injections is to perform a t-test on the means of the results? I've been told that I can take the means and compare them using RSD but this seems very wrong to me....

Originally Posted by topcat2000

Hi Guys, hope you can help!

I'm doing some chemistry analysis in which I run 6 replicate injections of my standard preparation, followed by my sample injections. However, in order to ensure the system is running ok, I run 2 injections of the same standard prep after every 6 sample injections.
Am I right in thinking the best (only?) way of comparing the initial 6 standard injections with the first 2 system suitability injections is to perform a t-test on the means of the results? I've been told that I can take the means and compare them using RSD but this seems very wrong to me....

This has stood for more than a day so I'll toss my two cents in and say that I'd use a t-test.