I will use the following notation:
EVPV=expected value of process variance
VHM=variance of hypothetical mean
TV=total variance
I am wondering how to calculate the VHM because in some case VHM=TV - EVPV
and in other case they calculate the VHM as Summation [prob. of Xi * (Xi -
E(x)) ]. Why sometimes it's the first formula that they use and sometimes
the second one ?
Dimitra