In a study of treatments for very painful "cluster" headaches, 153 patients were treated with oxygen and 154 other patients were given a placebo consisting of ordinary air. Among the 153 patients in the oxygen treatment group, 126 were free from headaches 15 minutes after treatment. Among the 154 patients given the placebo, 22 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. Identify the test statistic. z= (Round to two decimal places as needed.) Identify the P-value. P-value = (Round to three decimal places as needed.) What is the conclusion based on the hypothesis test? The P-value is the significance level of α=0.01, so the null hypothesis. There evidence to support the claim that the cure rate with oxygen treatment is higher than the cure rate for those given a placebo. b. Test the claim by constructing an appropriate confidence interval. The 98% confidence interval is <(p 1
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−p 2
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)< The 98% confidence interval is <(p 1
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−p 2
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)< (Round to three decimal places as needed.) What is the conclusion based on the confidence interval? Because the confidence interval limits 0, it appears that the two cure rate are Because the confidence interval limits include values, it appears that the cure rate is for the oxygen treatment than for the placebo. c. Based on the results, is the oxygen treatment effective? A. The results suggest that the oxygen treatment is not effective in curing "cluster" headaches because the cure rate for the oxygen treatment appears to be lower than that of the placebo. B. The results suggest that the oxygen treatment is effective in curing "cluster" headaches. C. The results suggest that the oxygen treatment is not effective in curing "cluster" headaches because the cure rates appear to be the same. D. The results are inconclusive