Function poisson_rate_test::one_tailed_ratio

pub fn one_tailed_ratio(
    num_events_one: f64, 
    t_one: f64, 
    num_events_two: f64, 
    t_two: f64, 
    h0_rate_ratio: f64
) -> f64

Conducts a likelihood ratio test (LHR) to determine if the two rates, r1 and r2, satisfy R>=r1/r2 for a ratio R.

The returned value is the probability of observing these two data sets given that r1/r2=R

See: >Gu, Ng, Tuang, Schucany 2008 “Testing the Ratio of Two Poisson Rates”`

Example: Testing two unequal rate events

use poisson_rate_test::one_tailed_ratio;
 
let occurances_observed = vec![0,0,1,0];
let occurances_other = vec![1,1,5,3,3,9];
let n1 = occurances_observed.len() as f64;
let n2 = occurances_other.len() as f64;
let sum1 = occurances_observed.iter().sum::<usize>() as f64;
let sum2 = occurances_other.iter().sum::<usize>() as f64;
//are these rates the same (e.g. 1.0 is the ratio of rates)?
let p = one_tailed_ratio(sum1, n1, sum2, n2, 1.0);
assert!(p<0.01); //<--confidently no