The hand strengths ARE in order of least to greatest possiblity as mentioned above. but remember that the probabilites were calculated as in dealing 5 cards randomly out of the 52 card deck.

as for actual card ranking (like ace high beating queen high, or a pair of 8s beating a pair of 4s), that of couse was arbitrarily chosen since having any pair or straight or flush is just as likely as any other ranked hand of the same type.