An inside straight is a would-be straight with a hole in the middle. 9? 2? 10? 8? 6? is an inside straight because only a 7 will turn it into a straight.  The distinction between outside straights and inside straights is important because in Jacks or Better we will never try to turn an inside straight into a straight.  It's too hard, since we have only one chance of completing the straight.

Actually, this is somewhat of a trick question. If you are talking about a relatively short amount of play, the answer is yes they can do better than players using a proper strategy. As with all things based on randomness, it is possible that someone who plays hunches or bases their hold decisions on the flow of the game can do better than a player how strictly follows the proper strategy in the short term. In the long run, however, the player who uses the strategy will always come out ahead.

Video Poker belongs to the small number of casino games, where thousands of players manage not just to make a living playing it, but to end up in possession of tremendous amounts of money. At the same time, tens of thousands of players around the world are in possession of sufficient knowledge of the game, so that they are able to have an astonishing experience during casino vacations, while also being able to take advantage of other benefits – and all that at a much lesser price than retail.
A straight is a hand with consecutive ranks, like 9? 7? 10? 8? 6?.  Notice again that the cards don't have to appear in order.  The order of face cards, from lowest to highest, is Jack, Queen, King, Ace, which we abbreviate J, Q, K, A.  An ace can also count as 1, to complete a straight where the other cards are 2, 3, 4, and 5.  But it can't count as both a low and a high card, e.g., Q K A 2 3.