Using Chi Square Statistic To Produce A Handicapping Method

[TrifectaMike]

If there is sufficient interest, I will along with any PA member(s) will go through the process of generating a handicapping method based on the Chi Square statistic.

I (We) will do it in a such a manner which will be non-technical, easy to understand, using only basic arithmetic, and will allow for anyone to participate.

The end result I believe will be a profitable system.

We will need someone with a large database to provide data for the factors that we will test, and include in our model.

If there is interest I will proceed.

Let me know.

Mike

[Dave Schwartz]

I can tell you that I am certainly interested to see this.

[Hochay]

Please allow me to partake and supply any information that i may help obtain.

[HandyKapper]

Absolutely count me in.

[Tom]

I will help anyway I can.

[TrifectaMike]

The Chi Square Statistic

Types of Data:

There are basically two types of random variables and they yield two types of data: numerical and categorical.

Categorical variables yield data in particular categories.
Responses to such questions as "What is your hair color?" or Do you own a
home?" are categorical because they yield data such as "biology" or "yes/no."

Numerical variables yield data in numerical form.
Responses to such questions as "How tall are you?" or "What is your
age?" are numerical.

Numerical data can be either discrete or continuous.
The table below may help you see the differences between these two variables.

Data Type Question Type Possible Responses
Categorical What is your sex? male or female
Numerical Discrete- How many jackets do you own? four or five
Numerical Continuous - How old are you? 42 years

Discrete data arise from a counting process, while continuous data
arise from a measuring process.

The Chi Square statistic compares the counts of categorical responses between two (or more) independent groups.

Chi square tests can only be used on actual numbers and not on percentages, proportions, means, etc.

Since I want all interested to understand the process, I will answer questions. No question is too simple or foolish... be free to ask and open. However, I will not answer any theoretical questions nor will I attempt to be rigorous. I will make up terms in the process, which may not be mathematically correct, but I will do so when necessary to clarify a point.

Mike

Next, I will use the "standard" dice example to explain the process.

[ceejay]

I expect that this will be an interesting thread/topic.

Mike,
Regarding discrete vs. continuous numerical data. Are you saying that uncertainty in discrete data arises from measurement uncertainty whereas uncertainty in continuous data is caused by measurement imprecision? Somebody answering the question "how are you?"with 42 as the answer really means "42.50 plus or minus 0.50."

[Robert Goren]

I will be interested this too. I looked into this back in the 70s and gave it up because at the time the compiling of the data was not feasible. I did a regression instead. Good luck

[raybo]

This may sound whimsical, to those who have worked in, or, have studied statistical functions (?) (which I sadly have not), but, what is the syntax for a "Chi Square" test? And, what is the reasoning behind using this function(?)? What does one hope to achieve as a result of the test?

[TrifectaMike]

Originally Posted by ceejay

I expect that this will be an interesting thread/topic.

Mike,
Regarding discrete vs. continuous numerical data. Are you saying that uncertainty in discrete data arises from measurement uncertainty whereas uncertainty in continuous data is caused by measurement imprecision? Somebody answering the question "how are you?"with 42 as the answer really means "42.50 plus or minus 0.50."

There is no need to go into measurement error(s) or uncertainty of measurements. The point is that we will use statistical data that can be counted or tallied.

For example:

How many horses won or lost their next race after finishing second in their previous race. We will use a Chi Square statistic to determine significance (or lack of significance) for that factor, and then compute a weight for that factor. We are jumping ahead, but I do want you to understand.

Mike

[GameTheory]

I've done this sort of thing many times, never came up with a profitable system though. Will be interested to see what you come up with...

[TrifectaMike]

Originally Posted by raybo

This may sound whimsical, to those who have worked in, or, have studied statistical functions (?) (which I sadly have not), but, what is the syntax for a "Chi Square" test? And, what is the reasoning behind using this function(?)? What does one hope to achieve as a result of the test?

I believe the "reason behind using the function" and what we can achieve will be become clear after the dice example and after we test a factor. As I said I will not go into the theoretical aspects of the distribution. The symbol is unimportant.

The information we will use will be in table form.

Mike

[TrifectaMike]

Originally Posted by GameTheory

I've done this sort of thing many times, never came up with a profitable system though. Will be interested to see what you come up with...

It will depend on the factors we select and test. And we will weight them. The same can be said about any approach. As you probably know we will not be using speed/pace ratings.

I believe we can make approach work during the testing phase by eliminating certain categories of races.

Mike

P.S. Join in we'll all have a hand in choosing the factors.

[Robert Goren]

The one thing I will say about this project. Chi-Square is known for producing some very strange relationships. Be very careful that you don't get a bunch of Gobbly Goop.

[TrifectaMike]

Originally Posted by Robert Goren

The one thing I will say about this project. Chi-Square is known for producing some very strange relationships. Be very careful that you don't get a bunch of Gobbly Goop.

Maybe I don't understand your post, but Chi-Square doesn't produce any relationships.

Mike