Toxicity of syphilis drug on mice
Use this example to explain that:
Drag the red line on the vertical axis upwards to apply a power transformation to the survival time.
A log transformation linearises the relationship and also gives residuals with fairly constant spread.
Fortunately, the same transformation of the response that linearises the relationship often also results in fairly constant error standard deviation.
The data set results from an experiment in which the toxicity of neoarsphenamine, a drug that was once used for the cure of syphilis, was tested in mice. Each mouse was given an intravenous injection of a solutions containing one of seven different concentrations of the drug.