2 . In a study of the long- run and short - run demands for money , Chow estimated the following* demand equation ( standard errors in parentheses ) for the United States from 1947: 1 through 1965: 4:1 = 0. 14 + 1.015 - 0.018 - 0.75R. W ( 0.15 ) ( 0.10 )` ( 0.015 ) = 0.996 R Z DW = 0.88 N = 76 ( quarterly ) where : M . = The log of the money stock in quarter I = The log of permanent income ( a moving average of previous quarters" current* income ) in quarter ! Y . = The log of current income In quarter ! " = The log of the rate of interest in quarter