as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
what is the standard deviation and mean return of oil?
user
oil as a commodity or investing in oil companies as a stock?  as a commodity, i'd recommend none. the article commodities – they have (almost) no place in your portfolio and the case against commodities explain why commodities are not good investments.
assistant