Inferential Regression Slope

Fit a straight line $y=\text{slope}\cdot x+\text{intercept}y=\backslash text\{slope\}\backslash cdot\; x+\backslash text\{intercept\}$ to paired data by ordinary least squares. x and y must have the same length.

Implement solve(x,y).

Returns. Return a tuple (slope, intercept) of floats. A different length raises ValueError. If all x values are equal the slope is undefined.

Examples

Example 1

Input:

solve([1.0, 2.0, 3.0], [2.0, 4.0, 5.0])

Output:

(1.5, 0.666667)

Example 2

Input:

solve([0.0, 1.0, 2.0, 3.0], [1.0, 3.0, 5.0, 7.0])

Output:

(2.0, 1.0)