A or B

[stho1978]

Hi,

I'm trying to work out the probability, and therefore the odds, of one of a selection occurring (A or B) - so they can't both happen. EG given I know the odds of each correct score happening, how do I find the following:

the score to be, either:

1-0. 1-1. 2-1 or 2-2?

1-0 = 7.0 (decimal odds),

1-1 = 7.5,

2-1 = 8

2-2 = 17

Thanks

 

[liero1]

1 / decimal odds = probability

 

[stho1978]

Hi

 

Thanks. I know that though (how to convert decimal odds to probability). I'm looking for the odds of one of several outcomes happening. EG the score to be either 1-0, 2-0 or 3-0. What are the odds of the correct score being one of those scores?

[liero1]

5 minutes ago, stho1978 said:

Hi

 

Thanks. I know that though (how to convert decimal odds to probability). I'm looking for the odds of one of several outcomes happening. EG the score to be either 1-0, 2-0 or 3-0. What are the odds of the correct score being one of those scores?

you add up the probabilities, that's it

[giraldi]

As Liero1 said, you can say that the probabilities are (1/decimal odds) .

So you can calculate probability for 1-0 as

p(1-0)=1/7 = 0.1428*100=14.28% and so on

Then as a general rule when you see "or" you will add the probabilities and if you see "and" you multiply them

So, 1-0 or 1-1 or 2-1 or 2-2 means that you have to add all the probabilities then will give you around 49%

 

Later edit: sorry did not see Liero1 just answered....

On the other hand those 1/7 ...etc to not be confused with the real probabilities to happen the event but this is other discussion ..

 

Edited January 23, 2019 by giraldi

[stho1978]

Ahhhh - course you do. That makes total sense. I knew how to work out the "and" (multiply them) but couldn't figure out the "or". Which of course is as simple as adding them. The answer's right there really given a sports book is made up of all the probabilities (perfect book  - Betfair - 100%).

 

Thanks both of you.