SUB normalization(ndiff,R2cum(),norm())
    PRINT "time difference","   <R2>"
    PRINT
    FOR idiff = 1 to ndiff
        IF R2cum(idiff) > 0 then
           LET R2bar = R2cum(idiff)/norm(idiff)
           PRINT idiff,R2bar
        END IF
    NEXT idiff
END SUB