example [🇷 for BE/BA]

posted by Aceto81 – Belgium, 2008-10-17 14:30 (5641 d 21:03 ago) – Posting: # 2548
Views: 18,354

Dear Martin,

Thanks for the example!
The reason for the NA is the fact that the program was only selecting 2 samples, instead of the minimum of 3.
This was caused by the fact that there were 2 samples after 2x Tmax.
So infact this should return an NA for the method I think (correct me if I'm wrong).

Here is an implementation:

time <- c(0.08263463, 0.52824754, 1.17358567, 1.39767757, 2.47663194,  3.19031555, 3.97925368, 6.95466074, 7.42732263, 12.08734425, 12.35692940, 13.63305248, 21.64587886, 29.33632297)
conc <- c(1.175213, 8.748377, 12.650698, 12.741200, 12.965722, 13.648985, 13.633996, 11.110552, 16.232875, 6.747145, 7.156791, 7.776978, 3.241740, 1.528261)

dat <- data.frame(time=time, conc=conc)

n_TTT_ARS=0
r.adj2=0
tp <- min(seq_along(dat$time)[dat$time>=dat$time[which.max(dat$conc)]*2])
if ((nrow(dat) - tp + 1) >=3) { #modification
for (i in
(nrow(dat)-2):(min(seq_along(dat$time)[dat$time>=dat$time[which.max(dat$conc)]*2])))
  {
  check <- summary(lm(log(conc)~time,dat[i:nrow(dat),]))$adj.r.squared
 
    if ((r.adj2 - check <(0.0001))) {
      n_TTT_ARS = nrow(dat)-i+1
      r.adj2 = summary(lm(log(conc)~time,dat[i:nrow(dat),]))$adj.r.squared
    }
  }
} else {n_TTT_ARS = NA} #modification


Ace

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