Function rgsl::statistics::variance

pub fn variance(data: &[f64], stride: usize, n: usize) -> f64

This function returns the estimated, or sample, variance of data, a dataset of length n with stride stride. The estimated variance is denoted by \Hat\sigma² and is defined by,

\Hat\sigma² = (1/(N-1)) \sum (x_i - \Hat\mu)²

where x_i are the elements of the dataset data. Note that the normalization factor of 1/(N-1) results from the derivation of \Hat\sigma² as an unbiased estimator of the population variance \sigma^2. For samples drawn from a Gaussian distribution the variance of \Hat\sigma² itself is 2 \sigma⁴ / N.

This function computes the mean via a call to gsl_stats_mean. If you have already computed the mean then you can pass it directly to gsl_stats_variance_m.