Struct average::Variance
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pub struct Variance { /* fields omitted */ }
Estimate the arithmetic mean and the variance of a sequence of numbers ("population").
This can be used to estimate the standard error of the mean.
Example
use average::Variance; let a: Variance = (1..6).map(Into::into).collect(); println!("The mean is {} ± {}.", a.mean(), a.error());
Methods
impl Variance
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fn new() -> Variance
Create a new variance estimator.
fn add(&mut self, sample: f64)
Add an observation sampled from the population.
fn is_empty(&self) -> bool
Determine whether the sample is empty.
fn mean(&self) -> f64
Estimate the mean of the population.
Returns 0 for an empty sample.
fn len(&self) -> u64
Return the sample size.
fn sample_variance(&self) -> f64
Calculate the sample variance.
This is an unbiased estimator of the variance of the population.
fn population_variance(&self) -> f64
Calculate the population variance of the sample.
This is a biased estimator of the variance of the population.
fn error(&self) -> f64
Estimate the standard error of the mean of the population.
fn merge(&mut self, other: &Variance)
Merge another sample into this one.
Example
use average::Variance; let sequence: &[f64] = &[1., 2., 3., 4., 5., 6., 7., 8., 9.]; let (left, right) = sequence.split_at(3); let avg_total: Variance = sequence.iter().map(|x| *x).collect(); let mut avg_left: Variance = left.iter().map(|x| *x).collect(); let avg_right: Variance = right.iter().map(|x| *x).collect(); avg_left.merge(&avg_right); assert_eq!(avg_total.mean(), avg_left.mean()); assert_eq!(avg_total.sample_variance(), avg_left.sample_variance());
Trait Implementations
impl Debug for Variance
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impl Clone for Variance
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fn clone(&self) -> Variance
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0
Performs copy-assignment from source
. Read more
impl Default for Variance
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impl FromIterator<f64> for Variance
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fn from_iter<T>(iter: T) -> Variance where
T: IntoIterator<Item = f64>,
T: IntoIterator<Item = f64>,
Creates a value from an iterator. Read more