"I know the coding , , where is the assumed mean and is the scaling factor .
Normally , the is the classwidth . What if the classwidth for every classes is different , what is h then ? Can still be one of the classwidth , i don think that makes sense."
The coding is only a matter of convienience, it does not matter what you chose as long as it makes the arithmetic easier. If it does not make the arithmetic easier then don't code.