I would want to calculate LD50 and LT50 from a dataset organized in 6 columns:
- Name of the compound (I just got 1 compound named A)
- Concentration of the compound (2 dilutions per compound)
- Individual number (a fixed number of 10 individuals is used per assay)
- State of the individual at the end of the experiment (1 = alive, 0 = dead)
- Day death (experiment last 15 days)
- Experiment number (2 replicates of the same experiment)
I drawn kaplan-meyer survival curves (y = day death, censor = state at the end of the experiment). Now I would want to calculate LD50 and LT50 using probit regression but I don't know how to process, could someone help me ?