zepid.calc.utils.risk_ci¶

zepid.calc.utils.risk_ci(events, total, alpha=0.05, confint='wald')

Calculate two-sided risk confidence intervals

Risk is calculated from

$R = \frac{a}{a+b}$

Wald standard error is

$SE_{Wald} = \left(\frac{1}{a} - \frac{1}{b}\right)^{\frac{1}{2}}$

Hypergeometric standard error is

$SE_{HypGeo} = \left(\frac{a b}{(a+b)^2 (a+b-1)}\right)^{\frac{1}{2}}$
Parameters: events (integer, float) – Number of events/outcomes that occurred total (integer, float) – Total number of subjects that could have experienced the event alpha (float, optional) – Alpha level. Default is 0.05 confint (string, optional) – Type of confidence interval to generate. Current options include Wald or Hypergeometric confidence intervals Tuple containing risk, lower CL, upper CL, SE tuple

Note

Confidence intervals rely on the central limit theorem, so there must be at least 5 events and 5 nonevents

Examples

Estimate the risk, standard error, and confidence intervals

>>> from zepid.calc import risk_ci
>>> r = risk_ci(45, 100)


Extracting the estimated risk

>>> r.point_estimate


Extracting the lower and upper confidence intervals, respectively

>>> r.lower_bound
>>> r.upper_bound


Extracting the standard error

>>> r.standard_error