How can I compare mean of subpopulation with mean of entire population? I want to compare mean of specific method with mean of all methods in a proficiency testing(PT) program.
A PT program is a program in which an organisation which executes PT, sends samples to multiple participants and ask them to measure some characteristics in sent sample. After a deadline participants send their results to PT provider. Provider analyse results in all and different groups. Groups are those who used same methods for measuring that characteristic.
