## 📊 Pearson Correlation

Measures the linear correlation (Pearson’s r) between two numeric columns.

### 🔹 Usage

```js
const table = Statistics.newTable({
  X: [10, 20, 30],
  Y: [15, 25, 35]
});

const correlation = table.compare("X", "Y").pearsonSample;

console.log(correlation.r);  // 1.0 (perfect correlation)
console.log(correlation.p);  // 0.0 (significant)
```

### 🔹 Interpretation

- `r` close to 1 or -1: strong correlation
- `p < 0.05`: statistically significant

### 🔹 Access
- `.pearsonSample` — uses sample variance
- `.pearsonPopulation` — uses population variance