The average chance of winning a prize is printed on the back of all Washington Scratch tickets. If the "average chance of winning a prize" is 1 in 5, this does not mean that there's an automatic winner within every five consecutive tickets. Prizes are distributed randomly throughout the total game and there is no pattern as to where they will occur.
Odds are determined by a simple calculation: take the total number of tickets in a game and divide it by the total number of prizes in that game. Tickets divided by prizes equals overall odds.
Consider this example:
There are 100 marbles in the mixed bag illustrated above. Assume that the red marbles are 'prizes'. 100 total marbles divided by 20 red ones ('prizes') means there's a 1 in 5 chance of blindly reaching-in and getting a red. However, whole handfuls might be grasped that don't contain a single red... while an occasional handful gets 2 or 4! It's called 'the luck of the draw' and it's simply a matter of random chance.