where:
Rjt = the geometric mean'2 of the daily rates of return of security j, over a five consecutive trading-day period, t,
Rmt = the geometric mean of the daily rates of return of Standard and Poor's Industrial stock Price Index, over a five consecutive trading-day period, t,
f1j = covariance (4jt, Rmt)/variance (1Rmt),
xj = E(Rjt) - BjE(Rmt), and
Ejt= disturbance term of security j at period t, and E(,jt) = 0.