Your Uses For the Correlation Function in Excel

[Grizzly Joe]

How have you used the Correlation Function in Excel to help you study what works with your predictions for sports gambling?

I've been experimenting with it, finding the correlation between columns of prediction and result data, and would like to hear of any one else's experiences and uses for it.

[uva3021]

Correlations are a very valuable tool. Some variables relate highly with others and it can help you with your capping. Its a delicate process however, and you need to assess all the data and the content of each variable, and understand the nature of sample sizes. Over time most variables will hover around a central tendency with an occasional outlier, so I would suggest graphing the two variables you are relating in respect to time, and see if the line in the graph stabilizes. If it oscillates wildly, then correlations are meaningless, for its probably random, and you would need a higher sample size.

A lot of things correlate without much regard to logic or reason other than an obvious empty relationship. For instance, anything that increases steadily will correlate highly with the distance of Haley's comet from the earth.

Do you mind sharing what kind of data you are working with?

[Grizzly Joe]

Originally Posted by uva3021

Do you mind sharing what kind of data you are working with?

I've tried different things...

For example finding the correlation factor between various predictive stats like for hockey:

[team total goals/g avg] or
[goalie save % avg's] or
[team penalty min/g avg]

with:
[actual goals/g] from the games on a particular night

By doing this over time, one can see if there is a positive or negative correlation between the factors, and see which ones are more able to accurately predict the final score... for over/under betting purposes...

Another thing i`ve been looking at is how accurate that certain fantasy sites are in predicting the outcomes for NFL player props, like number of QB completions, RB total rush yardage etc.

If one looks at columns of predictions from various sites, then finds the correlation factor between each column and the actual results, one can find out which fantasy site is the best at those predictions.

[uva3021]

Originally Posted by Grizzly Joe

If one looks at columns of predictions from various sites, then finds the correlation factor between each column and the actual results, one can find out which fantasy site is the best at those predictions.

great idea

[jarhead60]

I will say what uva said in different words..and he is correct.

Spread sheets like Excel are great tools. There are some challenges when using correlation and other statistical tools.

Get a college level statistics textbook at a used book store. How you set up the data, what you compare to what is important. The sample size is important.

But it is important to understand is that CORRELATION DOES NOT MEAN CAUSATION.

Be careful using averages...using averages to averages can yield r's that are too high.

The following site will calculate "p" from "r" and degrees of freedom for free P value calculator

The next logical step up from correlation is regression. Good luck.