Answer:
There is no way to determine the odds for a slot machine other than a poker game. The payout odds for a slot machine are not displayed anywhere on the machine. Only the pays are displayed and you cannot determine the odds from this info.
Since all of the game info is available for poker, if you have one of the many poker books available you can determine the odds for these games. There are too many unknown variables with slot machines.
ALL gaming machines,MUST,by law,now clearly display overall % odds,(usually quite close to coin aperture),by way of a small 'plaque/sticker',quoting something like: 'This machine is designed to pay out a minimum of ** %,however a sucession of close wins may reduce overall odds''
That's most simple way of getting an idea of what's available to you.
However,there is an alternative to this,(although I wouldn't recommend it !),is to obtain a 'refill key',(easily available on eBay for couple of £'s),these are a universal fitting for most slot machines in Great Britain,although Iv'e heard they are going to be changing this shortly.
With key,just insert into 'fruitie',and on LCD,there will be a display on view,and by using various hold buttons,which vary with each make/model,you can easily see many details the owner/operator doesn't want you to know,believe me!IE:last payout,% payout setting,% payout achieving,and probably most important exactly how much ££'s is obtainable from hopper/chute.,plus a lot of other valuable info if you are planning on playing that certain machine.
Hope that helped a little in your question