statsmodels.stats.rates.confint_poisson_2indep¶
- statsmodels.stats.rates.confint_poisson_2indep(count1, exposure1, count2, exposure2, method='score', compare='ratio', alpha=0.05, method_mover='score')[source]¶
Confidence interval for ratio or difference of 2 indep poisson rates.
- Parameters:
- count1
int
Number of events in first sample.
- exposure1
float
Total exposure (time * subjects) in first sample.
- count2
int
Number of events in second sample.
- exposure2
float
Total exposure (time * subjects) in second sample.
- method
str
Method for the test statistic and the p-value. Defaults to ‘score’. see Notes.
ratio:
‘wald’: NOT YET, method W1A, wald test, variance based on observed rates
‘waldcc’ :
‘score’: method W2A, score test, variance based on estimate under the Null hypothesis
‘wald-log’: W3A, uses log-ratio, variance based on observed rates
‘score-log’ W4A, uses log-ratio, variance based on estimate under the Null hypothesis
‘sqrt’: W5A, based on variance stabilizing square root transformation
‘sqrtcc’ :
‘exact-cond’: NOT YET, exact conditional test based on binomial distribution This uses
binom_test
which is minlike in the two-sided case.‘cond-midp’: NOT YET, midpoint-pvalue of exact conditional test
‘mover’ :
diff:
‘wald’,
‘waldccv’
‘score’
‘mover’
- compare{‘diff’, ‘ratio’}
Default is “ratio”. If compare is diff, then the hypothesis test is for diff = rate1 - rate2. If compare is ratio, then the hypothesis test is for the rate ratio defined by ratio = rate1 / rate2.
- alternative
str
The alternative hypothesis, H1, has to be one of the following
‘two-sided’: H1: ratio of rates is not equal to ratio_null (default)
‘larger’ : H1: ratio of rates is larger than ratio_null
‘smaller’ : H1: ratio of rates is smaller than ratio_null
- alpha
float
in
(0, 1) Significance level, nominal coverage of the confidence interval is 1 - alpha.
- count1
- Returns:
- tuple (low, upp)
confidence
limits.
- tuple (low, upp)