regression to the mean. How to find the coefficient of determination?

Question

Mathematics

Available data:
1. In 2016, striker Anton scored 24.75 goals out of n shots.
2. In 2017, striker Anton scored 28.22 goals from the n-th number of shots.
Regression formula to the mean: 100% x (1 – R)
The coefficient of determination is R2. How to find it in this case

Answer 1

The coefficient of determination is useless here.
To get the coefficient of determination, you need a lot of statistics and dependence y(x).
This comrade, as far as I understand, used a single lag as a model. I took many teams and football seasons, the model is how many points were received last year, the dependent variable is how many points this year.

Answer 2

Anton has delusions of grandeur. This is the usual approximation (one variable). If the sample had a parameter of the curling method (head, right heel, left, etc.), then with some stretch one could talk about regression.
lumpics.ru/coefficient-of-determination-in-excel