Host type
# of Doses
5.00
Μodel
a
1.43E-01
N50
3.54E+04
LD50/ID50
3.54E+04
Dose Units
Response
Agent Strain
2a (strain 2457T)
Exposure Route
Experiment Dataset
Description: 
Model data for Shigella flexneri (2a, strain 2457T) in the human [1]
Dose Illness Not illness Total
1E+04 1 3 4
1E+05 3 1 4
1E+06 7 1 8
1E+07 13 6 19
1E+08 7 1 8

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom
χ20.95,1 
p-value
χ20.95,m-k 
p-value
Exponential 73.6 70.2 4 3.84 
0
9.49 
3.89e-15
Beta Poisson 3.44 3 7.81 
0.329
Beta-Poisson fits better than exponential; cannot reject good fit for beta-Poisson.

 

Optimized parameters for the beta-Poisson model, from 10000 bootstrap iterations
Parameter MLE estimate Percentiles
0.5% 2.5% 5% 95% 97.5% 99.5%
α 1.43E-01 1.32E-02 2.12E-02 2.63E-02 2.90E-01 3.32E-01 4.27E-01
N50 3.54E+04 1.29E-11 8.16E-07 3.11E-04 3.34E+05 4.65E+05 9.68E+05

 

Parameter scatter plot for beta Poisson model ellipses signify the 0.9, 0.95 and 0.99 confidence of the parameters.

beta Poisson model plot, with confidence bounds around optimized model


References

  1. The response of man to virulent Shigella flexneri 2a, DuPont, Herbert L., and , Journal of Infectious Diseases, Volume 119, Number 3, p.296-299, (1969)