The `nodal' data frame has 53 rows and 7 columns.
The treatment strategy for a patient diagnosed with cancer of the prostate depend highly on whether the cancer has spread to the surrounding lymph nodes. It is common to operate on the patient to get samples from the nodes which can then be analysed under a microscope but clearly it would be preferable if an accurate assessment of nodal involvement could be made without surgery.
For a sample of 53 prostate cancer patients, a number of possible predictor variables were measured before surgery. The patients then had surgery to determine nodal involvement. It was required to see if nodal involvement could be accurately predicted from the predictor variables and which ones were most important.
data(nodal)A data frame with 53 observations on the following 7 variables.
A column of ones.
An indicator of nodal involvement.
The patients age dichotomized into less than 60 (`0') and 60 or over `1'.
A measurement of the size and position of the tumour observed by palpatation with the fingers via the rectum. A value of `1' indicates a more serious case of the cancer.
Another indicator of the seriousness of the cancer, this one is determined by a pathology reading of a biopsy taken by needle before surgery. A value of `1' indicates a more serious case of the cancer.
A third measure of the seriousness of the cancer taken from an X-ray reading. A value of `1' indicates a more serious case of the cancer.
The level of acid phosphatase in the blood serum.
Davison, A. C. (2003) Statistical Models. Cambridge University Press. Page 491.
data(nodal)
nodal.glm <- glm(r~aged+stage+grade+xray+acid,binomial,data=nodal)
summary(nodal.glm,correlation=FALSE)
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