Predict the Lethal Concentration at any specified time point for
a SurvFit object.
The function LCx, \(x\)\
the dose required to kill \(x\)\
after a specified test duration (time_LCx) (default is the maximum
time point of the experiment).
Mathematical definition of \(x\)\ denoted \(LC(x,t)\), is:
\(S(LC(x,t), t) = S(0, t)*(1- x/100)\),
where \(S(LC(x,t), t)\) is the survival probability at concentration \(LC(x,t)\) at time \(t\), and \(S(0,t)\) is the survival probability at no concentration (i.e. concentration is \(0\)) at time \(t\) which reflect the background mortality \(h_b\):
\(S(0, t) = exp(-hb* t)\).
In the function LCx, we use the median of \(S(0,t)\) to rescale the
\(x\)\
lcxt(fit, x, t, ...)# S3 method for SurvFit
lcxt(
fit,
x = 0.5,
t = NULL,
exposure_range = NULL,
interpolate_length = 50,
...
)
The function returns an object of class LCx, which is a list
with the following information:
X_propSurvival probability of individuals surviving considering the median of the background mortality (i.e. \(S(0, t)*(1- x/100)\)).
X_prop_providedSurvival probability of individuals surviving as provided in arguments (i.e. \((100-X)/100)\).
time_LCxA number giving the time at which \(LC_{x}\) has to be estimated as provided in arguments or if NULL, the latest time point of the experiment is used.
df_LCxA data.frame with quantiles (median, 2.5\
of \(LC_{X}\) at time time_LCx for \(X\)\
df_doseA data.frame with four columns: concentration, and median q50 and 95\
(qinf95 and qsup95) of the survival probability at time time_LCx.
An object used to select a method
rate of individuals dying (e.g., \(0.5\) for \(LC_{50}\), \(0.1\) for \(LC_{10}\), ...).
A number giving the time at which \(LC_{x}\) has to be estimated. If NULL, the latest time point of the experiment is used.
Further arguments to be passed to generic methods
A vector of length 2 with minimal and maximal value of the range of concentration. If NULL, the range is define between 0 and the highest tested concentration of the experiment.
of time point in the range of concentration between 0 and the maximal concentration. 100 by default. description.