## s2wR != mse, FDA != EMA [General Sta­tis­tics]

Dear Helmut, dear VStus,

I assume that the s2wR you have (or swR) is the intra-subject variance estimated with R data.
If this is the case the elaborate answer by Helmut is only valid if s2wR is equal to the MSE from the evaluation of all data, which is necessary for calculation of the point estimate and 90% CI of T versus R.

But s2wR = MSE is not necessarily true in all cases, although it is in many cases a reasonable assumption.

Moreover the FDA evaluation uses intra-subject constrasts to evaluate s2wR an µT-µR including the 90%CI whereas the EMA recommended method is bases on common ANOVA (aka GLM in SAS speak. Both evaluation methods give different results. Usually slight differences, but ...

Thus my answer to the question "Is it feasible to try calculation of 90% CIs?" for the EMA based on the results of a FDA evaluation is a clear No.

What you get by Helmuts calculations is only an approximate solution which may be good enough but may also terrible fail.

Regards,

Detlew