What does it mean when someones says The stock market is efficient? What are the implications for investing in the stock market?

1. If the yield to maturity is greater than the coupon rate, the price of the bond is greater than the par value.

________ 2. All else equal, interest rate risk is higher for bonds that have longer yield to maturity

________ 3. IRR is a good decision rule to use because for every project there is only one IRR.

________ 4. Unsystematic risk can be eliminated by diversifying.

________ 5. A market is efficient if it incorporates all available information