# zepid.calc.utils.odds_ratio¶

zepid.calc.utils.odds_ratio(a, b, c, d, alpha=0.05)

Calculates the odds ratio and confidence interval from count data

Odds ratio is calculated from

$OR = \frac{a}{b} / \frac{c}{d}$

Odds ratio standard error is

$SE = \left(\frac{1}{a} + \frac{1}{b} + \frac{1}{c} + \frac{1}{d}\right)^{\frac{1}{2}}$
Parameters: a (integer, float) – Count of exposed individuals with outcome b (integer, float) – Count of unexposed individuals with outcome c (integer, float) – Count of exposed individuals without outcome d (integer, float) – Count of unexposed individuals without outcome alpha (float, optional) – Alpha value to calculate two-sided Wald confidence intervals. Default is 95% confidence interval Tuple of OR, lower CL, upper CL, SE tuple

Examples

Estimate the odds ratio, standard error, and confidence intervals

>>> from zepid.calc import odds_ratio
>>> odr = odds_ratio(45, 55, 21, 79)


Extracting the estimated odds ratio

>>> odr.point_estimate


Extracting the lower and upper confidence intervals, respectively

>>> odr.lower_bound
>>> odr.upper_bound


Extracting the standard error

>>> odr.standard_error