In a study of treatments for very painful "cluster" headaches, 158 patients were treated with oxygen and 141 other patients were given a placebo consisting of ordinary air. Among the 158 patients in the oxygen treatment group, 109 were free from headaches 15 minutes after treatment. Among the 141 patients given the placebo, 29 were free from headaches 15 minutes after treatment. Use a 0.01 significance level to test the claim that the oxygen treatment is effective. Complete parts (a) through (c) below. Consider the first sample to be the sample of patients treated with oxygen and the second sample to be the sample of patients given a placebo. What are the null and alternative hypotheses for the hypothesis test? A. Ho: P1 = P2 OB. HO: P1 SP2 O C. Ho: P1 = P2 H1: P1 P2 H1 : P1 = P2 OF. HO: P1 2 P2 OD. Ho: P1 = P2 O E. HO: P1 # P2 H1 : P1 / P2 Hy : P1 # P2 H1 : P1 = P2 Identify the test statistic. z= (Round to two decimal places as needed.)