Model data for Shigella flexneri (2a, strain 2457T) in the human [1]
Dose |
Positive stool isolation |
No positive stool isolation |
Total |
180 |
6 |
30 |
36 |
5000 |
33 |
16 |
49 |
1E+04 |
66 |
21 |
87 |
1E+05 |
15 |
9 |
24 |
|
Goodness of fit and model selection
Model |
Deviance |
Δ |
Degrees
of freedom |
χ20.95,1
p-value |
χ20.95,m-k
p-value |
Exponential |
169 |
160 |
3 |
3.84
0 |
7.81
0 |
Beta Poisson |
8.73 |
2 |
5.99
0.0127 |
Neither the exponential nor beta-Poisson fits well; beta-Poisson is less bad. |
|
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 |
2.65E-01 |
1.47E-01 |
1.74E-01 |
1.87E-01 |
3.82E-01 |
4.09E-01 |
4.70E-01 |
N50 |
1.48E+03 |
5.60E+02 |
7.33E+02 |
8.26E+02 |
2.55E+03 |
2.78E+03 |
3.38E+03 |
|
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