In Reading 51, Blue Box Ex 5, they state that active risk is the square root of the sum of active weights times the active volatility squared for each security. I thought the active risk formula was the standard deviation of active returns --> S^2 (Rp - Rb) Ex 5
The active risk of the managed portfolio is the square root of the sum of active weights squared times the active volatility squared for each security, which gives [0.182 × 25.02 + 0.092 × 50.02 + (–0.18)2 × 25.02 + (–0.09)2 × 50.02]1/2 = 9.0%.