This question is about ACTG 384, an HIV clinical trial comparing four 3-drug HIV treatment regimens. One of the outcomes

[answerhappygod]

This question is about ACTG 384, an HIV clinical trial comparing
four 3-drug HIV treatment regimens. One of the outcomes was regimen
failure; for simplicity we just categorize this as "yes" versus
"no", ignoring the fact that some patients left the study earlier
than originally planned (so-called loss to follow-up). The relevant
data:
Treatment Number
of patients Number
of patients Number of patients
with
regimen failure without regimen
failure
1
155
76
79
2
155
66
89
3
155
56
99
4
155
74
81
a. Suppose that Pearson's chi-squared statistic is 6 (this
is in fact its rounded value). Carry out a hypothesis test for
dependence of treatment regimen and regimen failure using \alpha =
0.05α=0.05.*
b. Based on your answer in a., is it useful to know which
treatment regime a patient received when we want to predict whether
a patient will experience regimen failure?*