different Model determination with same data

[machenme]

I make a notebook with https://github.com/microsoft/ML-For-Beginners/tree/main/2-Regression/3-Linear and use same data.
here is my answer

If the value is 0, it means that the model does not take input data into account, and acts as the worst linear predictor, which is simply a mean value of the result. The value of 1 means that we can perfectly predict all expected outputs. In our case, the coefficient is around 0.06, which is quite low.

with same plot , but my answer is 0.0446 , did I have missing something?