Tasks of DEBtox
Last updated on 11 dec 2000
DEBtox basically serves six tasks:
- Estimation of parameters, their asymptotic standard deviations and
their correlation coefficients. The different modes of action of the compound
are described by different models: one for the survival experiment, three
for body growth, five for reproduction and three for population growth.
- Measurement of the goodness of fit of the selected model and a graphical
presentation of data together with the model expectations for the time
and the concentration profiles.
- Calculation of the profile ln likelihood function for the no-effect
concentration. The results are presented graphically. DEBtox reads this
graph and can produce confidence intervals, if the user has selected the
- Calculation of EC(e,t) values, ET(e,c) values and ER(c,t) values
and their standard deviations, if the user has selected the
concentration c, the exposure time t and/or the effect
level e. DEBtox can present the effect as a function of
concentration and exposure time graphically, using isoclines.
- Statistical tests on any parameter value or combination of parameter
values. This is done on the basis of the likelihood ratio test.
- Analysis of the residuals. The residuals, i.e. the differences between
observed values and model expectations, can be plotted as functions of
the concentration, the exposure time or the response.
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