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Experiment ID
87
Pathogen
Bacillus anthracis
Agent Strain
Vollum
Contains Preferred Model
Yes
Reference
June, R. ., Ferguson, W. ., & Worfel, M. . (1953). Experiments in feeding adult volunteers with Escherichia coli 55, B5, a coliform organism associated with infant diarrhea. American Journal of Hygiene, 57(2). https://doi.org/10.1093/oxfordjournals.aje.a119570
Exposure Route
inhalation
Response
death
Host type
guinea pig
# of Doses
4.00
Dose Units
spores
Μodel
exponential
k
1.65E-05
LD50/ID50
4.2E+04
Description
Guinea pig/Vollum Strain model data 
Dose Dead Survived Total
19800 8 24 32
40800 18 14 32
76200 21 11 32
118000 28 4 32

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value 		χ20.95,m-k 
p-value
Exponential 1.43 -0.000184 3 3.84 
1 		7.81 
0.699
Beta Poisson 1.43 2 5.99 
0.49
Exponential is preferred to beta-Poisson; cannot reject good fit for exponential.

 

Optimized parameters for the exponential model, from 10000 bootstrap iterations
Parameter MLE estimate Percentiles
0.5% 2.5% 5% 95% 97.5% 99.5%
k 1.65E-05 1.20E-05 1.30E-05 1.35E-05 2.03E-05 2.12E-05 2.28E-05
ID50/LD50/ETC* 4.2E+04 3.04E+04 3.27E+04 3.41E+04 5.14E+04 5.35E+04 5.80E+04
*Not a parameter of the exponential model; however, it facilitates comparison with other models.

 

Parameter histogram for exponential model (uncertainty of the parameter)

Exponential model plot, with confidence bounds around optimized model

Bacillus Graph 2.png

References