This description is courtesy of Dr Murray Jorgensen from the University og Waikato, New Zealand The Prostate Cancer clinical trial data of Byar and Green (1980) is reproduced in Andrews and Herzberg (1985, pp 261-247). It is also available in Statlib at the URL http://lib.stat.cmu.edu/datasets/Andrews/T46.1 This data set was obtained from a randomized clinical trial comparing four treatments for 506 patients with prostatic cancer. These patients had been grouped by physicians using clinical criteria into Stage 3 and Stage 4 of the disease. This is response variable, in column 13. There are twelve pre-trial covariates measured on each patient, seven may be taken to be continuous, four to be discrete, and one variable (Index of tumour stage and histolic grade) is an index nearly all of whose values lie between 7 and 15, and which could be considered either discrete or continuous. In column order, the covariates are: Age, Weight, Performance rating, Cardiovascular disease history, Systolic Blood pressure, Diastolic blood pressure, Electrocardiogram code, Serum haemoglobin, Size of primary tumour, Index of tumour stage and histolic grade, Serum prostatic acid phosphatase, and bonemetastasis. Continuous covariates: Age, Weight, Systolic Blood pressure, Diastolic blood pressure, Serum haemoglobin, Size of primary tumour, Index of tumour stage and histolic grade, Serum prostatic acid phosphatase Categorical covariates (Number of Levels): Performance rating (4), Cardiovascular disease history (2), Electrocardiogram code (7), Bone metastases (2) A preliminary inspection of the data showed that the size of the primary tumour (SZ) and serum prostatic acid phosphatase (AP) were both skewed variables. These variables have therefore been transformed. A square root transformation was used for SZ, and a logarithmic transformation was used for AP to achieve approximate normality. Observations that had missing values in any of the twelve pretreatment covariates were omitted from further analysis, leaving 475 out of the original 506 observations available. The original numbering is given in column 14.