Development of a web-based tool for probit analysis to compute LC 50 /LD 50 /GR 50 for its use in toxicology studies Vinay Kumar* Department of Mathematics and Statistics, CCS Haryana Agricultural University, Hisar -125004 (Haryana), India O.P. Sheoran Department of Mathematics and Statistics, CCS Haryana Agricultural University, Hisar -125004 (Haryana), India Sarita Rani Department of Mathematics and Statistics, CCS Haryana Agricultural University, Hisar -125004 (Haryana), India Komal Malik Department of of Economics, Govt. College, Nalwa, Hisar (Haryana), India *Corresponding author. Email: vinay.stat@gmail.com Article Info https://doi.org/10.31018/ jans.v12i4.2408 Received: October 26, 2020 Revised: December 3, 2020 Accepted: December 7, 2020 How to Cite Kumar V. et al. (2020). Development of a web-based tool for probit analysis to compute LC 50 /LD 50 /GR 50 for its use in toxicology studies. Journal of Applied and Natural Science, 12(4): 641 - 646. https://doi.org/10.31018/jans.v12i4.2408 This work is licensed under Attribution-Non Commercial 4.0 International (CC BY-NC 4.0). © : Author (s). Publishing rights @ ANSF. Published online: December 9, 2020 ISSN : 0974-9411 (Print), 2231-5209 (Online) journals.ansfoundation.org Research Article INTRODUCTION Probit analysis is widely used in research areas deal- ing with the binomial response. Its main application is observed in the field of toxicological studies, where it transforms the sigmoidal dose-response curve to a straight line that can further be easily analyzed by re- gression through either least squares or maximum like- lihood. The methodology transforms the complex per- centage affected vs. dose-response into a simple linear relation of probit vs. dose-response. The probit is then be translated into percentages. This method is appro- priate because of the typical shape found in the dose- response curve and although approximate but allows quantification of the consequence due to exposure. Lei and Sun (2018) compared lethal dose ratios using pro- bit regression with arbitrary slopes using bioassay data of chrysanthemum aphids, three populations of the pest bug “Wicked Witch of the West” and two popula- tions, of Godfather larvae. Singh and Zahara (2017) studied LC 50 assessment of cypermethrin in Hetero- pneustes fossilis using probit analysis. The term “Probit” is an abbreviation of the term “probability unit” and it was the first developed and studied to treat data such as the percentage of pest killed by a pesticide. Bliss (1934) proposed the trans- formation of the percentage killed into “probit”. He de- fined arbitrarily 0 for 0.0001 and 10 for 0.9999 and included a table to aid researchers to convert kill- percentage to probit, which then is plotted against the logarithm of dose. The table introduced by Bliss was further carried forward in the toxicological application by Finney (1952). Values tabulated by Bliss can be derived from probit by adding 5. Using Bliss’s idea of probit analysis, Leslie et al. (1945) were able to dis- cuss the distribution of body–weight of female rats where they reach maturity. Probit analysis is mainly used to analyze data from Abstract The toxicity bioassays are essential to detect and estimate the potential toxicological effects of chemicals on an organism. LC 50 /LD 50 /GR 50 is the estimation of dose/concentration necessary to kill 50 per cent of a population of the test species. Experi- mentally this is done by administrating a chemical at different doses to a group of organism and then observing the resulting mortalities in a set of the time period. A web-based module for a statistical analysis tool to calculate and compare the median lethal dose has been developed in ASP scripting language based on Server -Client Architecture. The module produces the final probit line, dose-response curve, LC 50 /LD 50 with 95 % confidence interval. The Chi -square statistic has been obtained for testing the adequacy of fit. A user-friendly interface for entering/pasting the data and various parameters such as number of variables, number of observations etc. has also been provided. Additionally, a complete procedure to perform probit analysis has also been provided in the help file. Keywords: Concentration, LC 50 /LD 50, Probit Analysis, Server-Client Architecture