Fig. 4. Survival probability in experiment 2 in (A) tumor-bearing mice receiving either chemotherapy (TC) or drug vehicle (TV) and (B) tumor cell vehicle–injected mice receiving chemotherapy (NTC). Day 0 is the day of chemotherapy (adriamycin 4.0 mg/kg and cyclophosphamide 61.5 mg/kg) or drug vehicle initiation. The first symbol represents the time at which the first death occurred in each housing condition. (A) For TV mice, survival probability was marginally greater in IG than in II mice (² = 3.243, p = .072). As expected, TC mice (N = 9 II, 23 IG, 13 GG, and 16 GI) had significantly greater overall survival probability than TV mice (N = 12 II, 19 IG, 12 GG, and 14 GI; ² = 57.778, p < .001). (B) For NTC mice (N = 12 II, 20 IG, 15 GG, and 11 GI), survival probability was significantly greater in II and GG mice than in IG mice (² = 7.626, p < .01 and ² = 5.752, p < .05, respectively) and marginally greater in GI than in IG mice (² = 2.812, p = .094). Survival probability was significantly higher in NTC than in TC mice (² = 32.561, p < .001).