mcframework.stats_engine.std

mcframework.stats_engine.std(x: ndarray, ctx: StatsContext) → float | None

Sample standard deviation with Bessel correction.

The estimator is

\[s = \sqrt{\frac{1}{n_\text{eff} - \texttt{ddof}} \sum_{i=1}^{n_\text{eff}} (x_i - \bar X)^2 }.\]

Parameters:

xndarray

Input sample.

ctxStatsContext

Uses ddof (default 1). If nan_policy="omit", non-finite values are excluded.

Returns

——-

float or None

\(s\) when \(n_\text{eff} > \texttt{ddof}\), else None.

Examples

>>> std(np.array([1, 2, 3]), {})
1.0