% and ratios

[BIG CHEESE]

how does a % become a ratio and why.
can i only use % in my thinking it seams easier.
be nice.

[dogmeat]

I'm not exactly sure what you are asking, but since a lot of players make a mistake when calculating their odds:

Many players get confused when figuring their odds, and also when they figure their pot odds. If you are drawing at a flush after the turn, and there are 9 suited cards that will win for you, you can simply divide 9 by the 45 remaining cards, and get 20%, or one chance in five of winning. This is expressed as a ratio of 1-4, not 5-1 against, that many players think. You will lose with the other 36 cards, so simply put it is 9-36 or 1-4.

If you divide the cards that will beat you by the cards that you win with, such as 9/36, then you get .25 which divided into the full 100% tells you the odds against your 1 chance of winning (100 divided by 25 = 4), so 4-1 against.

If I just made that all less clear for you, sorry.

Dogmeat [img]/images/graemlins/spade.gif[/img]

[jtr]

When you say ratio, you're talking about odds ratios, e.g., 4.2:1. One of the nice things about ratios versus percentages (or odds ratios versus probabilities) is that ratios can be multiplied together when looking at conditional probability questions. Along the same lines, ratios don't have an artificial cap at 0% or 100%.

That's why they can be a very useful format mathematically. And to transform a percentage to a ratio, you just want to think about the probability of something happening (e.g., your flush draw hitting) versus the probability of it not happening.

Example: we have one chance in 6 of getting killed if we play Russian roulette. That's about 17%. But expressed as an odds ratios, we have 5:1 odds in favour of our survival. This is because there are five chambers in the revolver that don't have a bullet in them, and one that does.

Finally, if percentages are easier for you, then that's OK, stick to them. It's just that thinking in terms of odds ratios is often very useful for quick calculations in poker problems, because we are so often comparing the odds against hitting our draw to the odds the pot is offering us.

Hope this helps.

Both of the posts above mine are terrific, but re-reading your question, I thought I might have a way of expressing what they said in a more direct fashion.

A percentage and a ratio are both expressions of the same thing; they both represent the same thing. Either can be used at any given time for figuring out whatever you need to, but the very nature of poker problems has naturally led people to use ratios when talking them.

Accordingly, if you are more comfy thinking in terms of percentages, then rock the heck on with the percentages. Your task is to then be able to convert the ratios you encounter into the percentage expression you want.

Now that I've typed all that out, I am not sure I really had anything to add to the discussion after all.. :-)

1:4= 1/5 = 20%
2:18= 2/20 = 10%
5:35= 5/40 = 12.5%
etc

dunno if that helps, but it seems like something along the lines of what you're asking