+--------+-------------------+
| leuk   | R Documentation   |
+--------+-------------------+

Survival Times and White Blood Counts for Leukaemia Patients
------------------------------------------------------------

Description
~~~~~~~~~~~

A data frame of data from 33 leukaemia patients.

Usage
~~~~~

::

    leuk

Format
~~~~~~

A data frame with columns:

``wbc``
    white blood count.

``ag``
    a test result, ``"present"`` or ``"absent"``.

``time``
    survival time in weeks.

Details
~~~~~~~

Survival times are given for 33 patients who died from acute myelogenous
leukaemia. Also measured was the patient's white blood cell count at the
time of diagnosis. The patients were also factored into 2 groups
according to the presence or absence of a morphologic characteristic of
white blood cells. Patients termed AG positive were identified by the
presence of Auer rods and/or significant granulation of the leukaemic
cells in the bone marrow at the time of diagnosis.

Source
~~~~~~

Cox, D. R. and Oakes, D. (1984) *Analysis of Survival Data*. Chapman &
Hall, p. 9.

Taken from

Feigl, P. & Zelen, M. (1965) Estimation of exponential survival
probabilities with concomitant information. *Biometrics* **21**,
826â€“838.

References
~~~~~~~~~~

Venables, W. N. and Ripley, B. D. (2002) *Modern Applied Statistics with
S.* Fourth edition. Springer.

Examples
~~~~~~~~

::

    library(survival)
    plot(survfit(Surv(time) ~ ag, data = leuk), lty = 2:3, col = 2:3)

    # now Cox models
    leuk.cox <- coxph(Surv(time) ~ ag + log(wbc), leuk)
    summary(leuk.cox)

