Valid Arguments vs. Strong Arguments

There is a slight difference between a valid argument and a strong argument. The premises in each type of argument are true. However, the truthfulness of the conclusion is where they differ. In a strong argument, the conclusion might not be true. Conversely, the conclusion is almost always true in a valid argument. Strong arguments often reveal or involve an opinion or a sense of bias by the person making the argument.

My examples:
Strong Argument - Team A defeated Team B. Team B defeated Team C. Therefore, Team A will be Team C.
      This is a strong argument because the conclusions may not be true. The premises, or the fact that Team A beat Team B, is true. However, just because Team C lost to Team B, does not necessarily mean that Team C will also lose to Team A. Although the conclusion may end up being true, it is not a guarantee that the result will be as stated.

Valid Argument - Dillon has the flu. Therefore, he has symptoms such as fever, aches, chills and fatigue.
      This is a valid argument because fever, aches, chill and fatigue are all symptoms of the flu. If the symptoms were different, then the diagnosis would probably be different as well.