Table 1.21 shows the times in days from remission induction to relapse for 51 patients with acute nonlymphoblastic leukemia who were treated on a common protocol at university and private institutions in the Pacific Northwest. This is a portion of a larger study reported by Glucksberg et al. (1981).

Table 1.21 Ordered Remission Durations for 51 Patients with Acute Nonlymphoblastic Leukemia (in days)

24 46 57 57 64 65 82 89 90 90 111 117 128 143 148 152 166 171 186 191 197 209 223 230 247 249 254 258 264 269 270 273 284 294 304 304 332 341 393 395 487 510 516 518 518 534 608 642 697 955 1160 Since data of this type are notoriously skewed, the distribution of the times can be examined using the following output from PROC UNIVARIATE in SAS as seen in Fig. 1.22.

(a) What is the relation between the mean and the median? What does this mean about the shape of the distribution? Do the stem and leaf plot and the box plot support this?

(b) Identify any outliers in this data set. Can you think of any reasons for these outliers? Can we just “throw them away”? Note that the mean time of remission is 292.39 days and the median time is 249.

(c) Approximatelywhat percent of these patientswere in remission for less than one year?