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The Datafile PD-CD 3
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Text File
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1994-04-11
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6KB
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120 lines
--------------------------------
Help file for !Pools
by Andrew Ayre
v1.02 (April '94)
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INTRODUCTION...
This application attempts to predict the results of football matches.
Pools predictors have been around for a long time, and you might have
thought: 'If someone comes up with a winning formula, they are hardly likely
to share it with everyone else are they.' Instead the writer of the program
makes their fortune by selling it.
I wrote this application just for fun. I don't think that the mathematics
behind it are good enough to enable anyone to win vast amounts of money.
After all, what do you expect for the price of a disc? If you want to take
predicting football results seriously, I suggest that you buy a suitable
program that will probably be a lot better than this one. If - on the
otherhand - you want to predict a few results, then see how well they
compare and gasp in amazement if you get a few right, then this is the
program for you.
GETTING STARTED...
Load the application onto the iconbar by double-clicking on the icon in a
filer window.
Click on the icon, and a large window will appear with 24 writeable icons.
You can enter up to 12 matches (which should be sufficient for 1 division),
by entering the team names into the icons (case isn't important). Pressing
RETURN will make the caret jump to the next one. Home teams go on the left.
Away teams go on the right. Note: you don't have to fill all of the icons.
When you have finished, click on 'Predict', and the results of all the
matches will appear on the right.
Press Menu over the window, and slide over 'Save' to bring up a standard
save box. Drag the icon to a filer window (or type in a pathname), and the
predictions will be saved as text files.
Note: when entering teams, you don't always need the full name. Eg:
'Blackburn Rovers' could be entered as 'Blackburn'. But if there are two
teams from the same place but with different endings Eg:'Manchester City'
and 'Manchester United', then the endings are required.
Also, I wouldn't advise making predictions for two teams from different
divisions, because the result would be rubbish. Eg: if you play the team at
the top of division 1 against the team at the top of division 2, then you
may get a draw. But the teams arn't similar in ability, because the team in
division 2 is playing worse teams then the team in division 1 is playing.
HOW IT WORKS...
In order to make predictions, the program has to know how well the teams
are doing. It knows this by consulting a text file called 'Database' that
contains lots of results of past matches. If you want to look at it, you
will find it in inside the application.
This version (1.02) has all the results from the 1992-93 season (2028
matches!).
You can update the database yourself by using the 'Update...' option from
the iconbar menu. Alternatively, you can wait until I release a new version
with all the 1993-94 results in. This will probably be when the new
yearbooks are printed.
Update...
Select 'Update...' from the iconbar menu, and a window will appear. This
window allows you to enter the results of matches. The top is for the home
team and score, and the bottom is for the away team and score.
Click in the large writeable icon at the top and enter the home team.
Press RETURN and the caret will move into the small box to the right. Enter
the home team's score. Press RETURN and enter the away team. Pres RETURN
again and enter the away team's score. Pressing RETURN or clicking on 'OK'
will store that match.
When you have finished entering matches, press Menu over the window, and
select 'Sve Database' to update the 'Database' file.
To the left of the icons for the team names are two option icons. If the
one next to the home team is selected, then when the match is stored, that
team will stay in that box allowing quick entry of results. The other option
icon works in the same way, but for the away team.
Make sure when you are entering teams, that you include the endings like
'City' or 'Rovers' or 'Town' or 'Hotspur'.
The case of the teams is not important.
The Mathematics...
This section describes how the computer takes the results of past matches,
and comes up with a prediction.
When you click on predict, each match you have entered is taken in turn:
The computer goes through the database looking for the home team, only
taking notice of matches where that team played at home. It keeps a running
total of the number of matches played and the number of goals scored. It
then finds the average number of goals scored per match, by dividing the
total number of goals by the number of matches.
The same is done for the away team, only taking notice of matches where
that team played away from home.
It now has two averages, and they can be used to describe a poisson
distribution for each team (I'll try not to bore you with A-Level maths
here). The probablility of each team scoring a certain number of goals can
them be calculated (using exponentials and factorials). Then to obtain a
probablilty of that result, they are multiplied together. Eg: if the
probability of the home team scoring 1 goal is 0.1, and the probability of
the away team scoring 0 goals is 0.2, then the probability of the result
being 1-0, is 0.1x0.2 = 0.02 (or 2%).
It now has the probability of 25 different results (0-0 to 4-4). All that
needs to be done now is to find the highest probability. The coresponding
result is the most likely one.
The reason why this program often gets the prediction wrong, is that the
difference between the largest probability and the second largest is often
something like 0.1% or even 0.01%!
Happy predicting!