13. Maes et al. (A-26) conducted a study to determine whether depression might be associated with serologic indices of autoimmune processes or active virus infections.

Four categories of subjects participated in the study: Healthy controls (1), patients with minor depression (2), patients with major depression without melancholia (3), and patients with major depression with melancholia (4). Among the measurements obtained for each subject were soluble interleukin-2 receptor circulating levels in serum

(sIL-2R). The results by subject by category of subject were as follows. We wish to know if we can conclude that, on the average, sIL-2R values differ among the four categories of patients represented in this study. Let a = .01 and find the p value. Use Tukey's procedure to test for significant differences among individual pairs of sample means.

Subject sIL-2R

(U / ml)

Subject Category Subject sIL-2R

(U / ml)

Subject Category 1 92.00 1.00 26 230.00 2.00 2 259.00 1.00 27 253.00 3.00 3 157.00 1.00 28 271.00 3.00 4 220.00 1.00 29 254.00 3.00 5 240.00 1.00 30 316.00 3.00 6 203.00 1.00 31 303.00 3.00 7 190.00 1.00 32 225.00 3.00 8 244.00 1.00 33 363.00 3.00 9 182.00 1.00 34 288.00 3.00 10 192.00 1.00 35 349.00 3.00 11 157.00 1.00 36 237.00 3.00 12 164.00 1.00 37 361.00 3.00 13 196.00 1.00 38 273.00 3.00 14 74.00 1.00 39 262.00 3.00 15 634.00 2.00 40 242.00 4.00 16 305.00 2.00 41 283.00 4.00 17 324.00 2.00 42 354.00 4.00 18 250.00 2.00 43 517.00 4.00 19 306.00 2.00 44 292.00 4.00 20 369.00 2.00 45 439.00 4.00 21 428.00 2.00 46 444.00 4.00 22 324.00 2.00 47 348.00 4.00 23 655.00 2.00 48 230.00 4.00 24 395.00 2.00 49 255.00 4.00 25 270.00 2.00 50 270.00 4.00 SOURCE: Dr. M. Macs. Used by permission.