probit

https://doi.org/10.1351/goldbook.14953
Probability unit obtained by adding 5 to the normal deviates of a standardized normal distribution of results from a dose-response study.
Notes:
  1. Addition of 5 removes the complication of handling negative values.
  2. A plot of probit against the logarithm of dose or concentration gives a linear plot if the response follows a logarithmic normal distribution. Estimates of the \(\pu{LD_{50}}\) and \(\pu{ED_{50}}\)) (or \(\pu{LC_{50}}\) and \(\pu{EC_{50}}\)) can be obtained from this plot.
Source:
PAC, 2009, 81, 829. (Glossary of terms used in ecotoxicology (IUPAC Recommendations 2009)) on page 932 [Terms] [Paper]