Verysimplestats

This is now a stable version, with the following API

| Functions |
| :-- |
| `mean(x: list) -> float` |
| `median(x: list) -> float` |
| `variance(x: list) -> float` |
| `standard_deviation(x: list) -> float` |
| `covariance(x: list, y: list) -> float` |
| `correlation(x: list, y: list) -> float` |
| `rsquared(x: list, y: list) -> float` |
| `ordinary_least_square(x: list, y: list) -> (float, float)` |
| `linear_forecast(slope: float, intercept: float, value: float) -> float` |
| `residuals(slope: float, intercept: float, x: float, y: float) -> float` |
| `linear_regression(x: list, y: list) -> LinearRegression` |

I lacked a very simple lib for statistics (and was not really happy about the ones I found) so here it is. It provides really simplistic float computation statistics indicators.

Supported functions

| Functions | Examples |
| :-- | :-- |
| `mean(x: list) -> float` | `mean([1, 2, 3, 4, 5])` |
| `median(x: list) -> float` | `median([5, 2, 6, 4, 1, 3])` |
| `variance(x: list) -> float` | `variance([1, 2, 3, 4, 5])` |
| `standard_deviation(x: list) -> float` | `standard_deviation([1, 2, 3, 4, 5])` |
| `covariance(x: list, y: list) -> float` | `covariance([1, 2, 3, 4, 5], [1, 2, 3, 4, 5])` |
| `correlation(x: list, y: list) -> float` | `correlation([1, 2, 3, 4, 5], [1, 2, 3, 4, 5])` |
| `rsquared(x: list, y: list) -> float` | `rsquared([1, 2, 3], [-1, -2, -3])` |
| `linear_regression(x: list, y: list) -> dict` | `linear_regression([1, 2, 3, 4, 5], [4, 4.5, 5.5, 5.3, 6])` |