Law0 min ago
Probability
Hi,
In UK horseracing the fav will win around 33% of all races.
In a 2 horse race each horse has a 50% chance of winning - I think.
Does the fav in that race still have 50% or 50+33% chance of winning?
Any ideas please.
Thank you
In UK horseracing the fav will win around 33% of all races.
In a 2 horse race each horse has a 50% chance of winning - I think.
Does the fav in that race still have 50% or 50+33% chance of winning?
Any ideas please.
Thank you
Answers
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In a two-horse race, the chances of each horse winning will only be 50-50 if they are equal in all respects. As soon as one horse has an advantage over the other, then it is more likely that that horse will win.
How likely it is will depend upon how much better one horse is over the other.
Lastly, the quoted figure of favourites winning 33 percent of races is an AVERAGE over many races with varying numbers participating in each. Obviously, the bigger the field, the greater the chance of one of the others beating the favourite.
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Here is another way of looking at it.
Consider three races each with 5 horses.
Your statistics would predict that the favourite would be beaten in two of those.
The favourite has raced against 12 individuals and has been beaten by just two of them.
If those had been raced as individual two-horse races, then the favourite would have won 10 and lost 2.
How likely it is will depend upon how much better one horse is over the other.
Lastly, the quoted figure of favourites winning 33 percent of races is an AVERAGE over many races with varying numbers participating in each. Obviously, the bigger the field, the greater the chance of one of the others beating the favourite.
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Here is another way of looking at it.
Consider three races each with 5 horses.
Your statistics would predict that the favourite would be beaten in two of those.
The favourite has raced against 12 individuals and has been beaten by just two of them.
If those had been raced as individual two-horse races, then the favourite would have won 10 and lost 2.
Probability doesn't work like this.
Using the same logic if it was one-horse race the odds would certainly not be 33%!
The odds depend on a horse's form and the other horses in the race.
33% is just an average. On some days 80% of favourites may win, and on the next day none may win, etc
In a two horse race if it was racing against a carthorse the odds would be nearer 95%.
Using the same logic if it was one-horse race the odds would certainly not be 33%!
The odds depend on a horse's form and the other horses in the race.
33% is just an average. On some days 80% of favourites may win, and on the next day none may win, etc
In a two horse race if it was racing against a carthorse the odds would be nearer 95%.
It is not appropriate to use probability theory in relation to horseracing.
Probability theory only works when random events (such as tossing a coin, throwing a die or spinning a roulette wheel) where every outcome is equally possible are considered.
As explained by the first two answers. horseracing is not a random event. Some horses can naturally run faster than others so each participant does not have an equal chance of winning. The fact that 33% of favourites win races in the UK does not mean that in any given race the favourite has a one in three chance of winning. The 33% is only a measurement of events that have taken place and this cannot be used as a guide to forecast the outcome of any one race.
Even the determination of the �favourite� is open to manipulation. The favourite is the horse on which most money has been placed. It�s rather like saying that if everybody at the roulette table places their money on number nine, then number nine must be favourite to come up. Of course it is no more likely to come up than any of the other numbers and its chances are not influenced by the number of people betting on it.
In your two horse example if the favourite has a 33% chance of winning then the other runner must have a 67% chance of winning (the probability of all the outcomes must add up to 100%). So based on that theory the favourite would have only half the chances of the non-favourite. This is clearly silly so hopefully you can see it will not work.
What you could say is that if you placed your money on the favourite in a large number of races, based on past results you might win about 33% of the time. But that�s about all you could say, and that has nothing to do with probability theory.
Probability theory only works when random events (such as tossing a coin, throwing a die or spinning a roulette wheel) where every outcome is equally possible are considered.
As explained by the first two answers. horseracing is not a random event. Some horses can naturally run faster than others so each participant does not have an equal chance of winning. The fact that 33% of favourites win races in the UK does not mean that in any given race the favourite has a one in three chance of winning. The 33% is only a measurement of events that have taken place and this cannot be used as a guide to forecast the outcome of any one race.
Even the determination of the �favourite� is open to manipulation. The favourite is the horse on which most money has been placed. It�s rather like saying that if everybody at the roulette table places their money on number nine, then number nine must be favourite to come up. Of course it is no more likely to come up than any of the other numbers and its chances are not influenced by the number of people betting on it.
In your two horse example if the favourite has a 33% chance of winning then the other runner must have a 67% chance of winning (the probability of all the outcomes must add up to 100%). So based on that theory the favourite would have only half the chances of the non-favourite. This is clearly silly so hopefully you can see it will not work.
What you could say is that if you placed your money on the favourite in a large number of races, based on past results you might win about 33% of the time. But that�s about all you could say, and that has nothing to do with probability theory.
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