You must understand that two types of gambling games are different, your slot must understand and also your sport is also more understanding, the two games that you mention have a different risk of loss, we don't talk nominal bet, we speak loss.

Slot: commonly done with manual spin, automatic and buy bonuses, the three features are often used by gamblers, the problem is your slot game plays and controlled by casino operators assigned to the game Slots, in the game you will never know the final results win and lose.
Sports betting: At least you can compare some games and opponents when the club you want to install, for example: Liverpool vs. Madrid, before the match or bet on the installed you know Liverpool Has a good chance and it can be analyzed to other clubs, to determine winning and losing.

Conclusion: If you talk about more loss, for me a bigger slot loss than sports betting.