Can I select mutual fund based on mutual fund ratings assigned?

This is a major myth. Remember, a mutual fund rating is based on the past performance of the fund. The past performance need not be repeated in future. Secondly, the mutual fund may have had a strategy that may have worked specifically in that period. That does not mean that in the changed circumstances its strategy will work. As a mutual fund investor you need to do your homework. Look at their past performance, look at their portfolio mix and try to understand what the fund manager is saying through his monthly notes. The MF ratings can be a starting point for your MF investment decision, but it cannot be a substitute for your investment decision.