# statsmodels.stats.oneway.confint_effectsize_oneway¶

statsmodels.stats.oneway.confint_effectsize_oneway(f_stat, df, alpha=0.05, nobs=None)[source]

Confidence interval for effect size in oneway anova for F distribution

This does not yet handle non-negativity constraint on nc. Currently only two-sided alternative is supported.

Parameters
f_statfloat
dftuple

degrees of freedom df = (df1, df2) where

• df1 : numerator degrees of freedom, number of constraints

• df2 : denominator degrees of freedom, df_resid

alphafloat, default 0.05
nobsint, default None
Returns
Holder

Class with effect size and confidence attributes

Notes

The confidence interval for the noncentrality parameter is obtained by inverting the cdf of the noncentral F distribution. Confidence intervals for other effect sizes are computed by endpoint transformation.

R package effectsize does not compute the confidence intervals in the same way. Their confidence intervals can be replicated with

>>> ci_nc = confint_noncentrality(f_stat, df1, df2, alpha=0.1)
>>> ci_es = smo._fstat2effectsize(ci_nc / df1, df1, df2)