skbio.diversity.alpha.chao1_ci(counts, bias_corrected=True, zscore=1.96)[source]#

Calculate Chao1 confidence interval.

counts1-D array_like, int

Vector of counts.

bias_correctedbool, optional

Indicates whether or not to use the bias-corrected version of the equation. If False and there are both singletons and doubletons, the uncorrected version will be used. The biased-corrected version will be used otherwise.

zscorescalar, optional

Score to use for confidence. Default of 1.96 is for a 95% confidence interval.


Chao1 confidence interval as (lower_bound, upper_bound).

See also



The implementation here is based on the equations in the EstimateS manual [1]. Different equations are employed to calculate the Chao1 variance and confidence interval depending on bias_corrected and the presence/absence of singletons and/or doubletons.

Specifically, the following EstimateS equations are used:

  1. No singletons, Equation 14.

  2. Singletons but no doubletons, Equations 7, 13.

  3. Singletons and doubletons, bias_corrected=True, Equations 6, 13.

  4. Singletons and doubletons, bias_corrected=False, Equations 5, 13.