If player A tries to pass to player B, two areas are drawn around A and B. The larger one is an ellipse, the smaller one almost a strip. Here you can see the areas that influences a pass.
Now the (preliminary) odds for success of that pass are
Pro = 4*(100/passlength)*(Strength of A)
versus
Contra = essentially the sum of all opponent player strengths in the strip plus 0.35 times the sum of the strengths of all additional opponent players inside the ellipse.
"Essentialy" means that these strengths are weighted slightly according to how central they are in these areas.

How are the odds for shots calculated? The (preliminary) odds for goal are
Pro = 10*(100/shotlength)*(Strength of A)
The opposing (preliminary) odds are the sum of two parts. The first one,
Contra1, is the same as for a pass. The second term is
Contra2 = (1/2)*(Strength of Goalkeeper)* (width of playfield)/(distance from Goalkeeper to ball).

In both cases, these preliminary odds, like 4 : 3, are not taken directly, but rather both numbers are first raised to the power of 1.5. Thus these preliminary odds of 4:3 transform into the final odds of 8 : 5.2.

How the computer trainers work