On page 297 of CMOS Circuit Design,Layout and Simulation by Baker 2ndedition, there is equation that defines the gm of a short channel MOSFET as

Gm=Vsat* Cox* W

Could you please tell me how should I use this equation to find the gm calculated in table 9.2 page 300 for NMOS!??
I know this is not accurate,a rough estimate is acceptable for me

Thanks alot