frac{4^2 + 6.9^2 - 4.2^2}{2 \times 4 \times 6.9}\) \(\cos{y} = 0.8327898 \dotsc\). Do not round this answer yet. To calculate the angle use the inverse cos button on the calculator (\(\cos^{-1}\)).

This function is a simple one-dimensional example used for illustrating methods of prediction for computer experiment output. Santner, T. J., Williams, B. J., & Notz ...