Donaldson Capital Management, a regional money management firm, manages nearly $400 million allocated among three investment managers. All portfolios have the same objective, which is to produce superior risk-adjusted returns (by beating the market) for their clients. You have been hired as a consultant to measure the performance of the portfolio managers. You have collected the following information based on the last ten years of returns.

| Portfolio Manager | Mean Annualized Rate of Return | Beta | Standard Deviation of Return |

|-------------------|-------------------------------|------|------------------------------|

| a | 0.18 | 1.35 | 0.24 |

| b | 0.21 | 1.95 | 0.25 |

| c | 0.24 | 2.10 | 0.22 |

During the same time period the average annual rate of return on the market portfolio was 13% with a standard deviation of 19%. In order to assess the portfolio performance of the above managers, you should use: