The excess return generated by the portfolio manager is calculated as the difference between the aggregate return of the portfolio and the aggregate return of the benchmark index.

Portfolio Return is calculated using the Portfolio Weights and Returns: = $(0.20 \times 10\%) + (0.15 \times 15\%) + (0.20 \times 20\%) + (0.10 \times 8\%) + (0.20 \times 18\%) + (0.15 \times 15\%)$ = $2.00% + 2.25% + 4.00% + 0.80% + 3.60% + 2.25%$= **`$14.90`%$**

Index Return is calculated using the Index XYZ Weights and Returns: = $(0.15 \times 12\%) + (0.10 \times 15\%) + (0.25 \times 22\%) + (0.05 \times 5\%) + (0.25 \times 10\%) + (0.20 \times 12\%)$ = $1.80% + 1.50% + 5.50% + 0.25% + 2.50% + 2.40%$= **`$13.95`%$**

Excess Return = Portfolio Return - Index Return = $14.90% - 13.95%$= **`$0.95`%$**