Palesh and colleagues (2007) tested the relationship between stress and the progression of breast cancer in women. They measured the progression of breast cancer among 94 women who experienced serious traumatic life events, standard stressful life events, or no stressful life events. They reported the following result: "A Kruskal-Wallis test found . . . differences among the three groups [χ2 (2) = 6.09, p = .047]" (Palesh et al., 2007, p. 237).
(a) How many groups were observed in this study, and what are the degrees of freedom for this test?
(b) Was this nonparametric test significant at a .05 level of significance?