Probit Analysis.

An alternative to the logistic analysis of dose-response data is probit analysis. In probit analysis, the model is

Φ−1(pj ) = α + β log(xj )

where Φ(·) is the cumulative distribution function of a standard normal distribution. Graph Φ(·) and the logistic cdf and compare the general shapes of the distributions. In light of the two previous exercises, give a brief summary of the similarities and differences of logit and probit analysis. For more information on probit analysis, the interested reader should consult Finney (1971).