It seems you are talking about high-functioning psychopaths, rather than psychopaths according to the diagnostic DSM-IV criteria. Thus the prior should be different from 0.03. Assuming a high-functioning psychopath is necessarily a psychopath then it seems it should be far lower than 0.03, at least from looking at the criteria:

A) There is a pervasive pattern of disregard for and violation of the rights of others occurring since age 15 years, as >indicated by three or more of the following: failure to conform to social norms with respect to lawful behaviors as indicated by repeatedly performing acts that are >grounds for arrest; deception, as indicated by repeatedly lying, use of aliases, or conning others for personal profit or pleasure; impulsiveness or failure to plan ahead; irritability and aggressiveness, as indicated by repeated physical fights or assaults; reckless disregard for safety of self or others; consistent irresponsibility, as indicated by repeated failure to sustain consistent work behavior or honor financial >obligations; lack of remorse, as indicated by being indifferent to or rationalizing having hurt, mistreated, or stolen from another; B) The individual is at least age 18 years. C) There is evidence of conduct disorder with onset before age 15 years. D) The occurrence of antisocial behavior is not exclusively during the course of schizophrenia or a manic episode."