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Angioplasty’s benefits challenged. Each year, more than 1
Chapter 8, Problem 56E(choose chapter or problem)
Problem 56E
Angioplasty’s benefits challenged. Each year, more than 1 million heart patients undergo an angioplasty. The benefits of an angioplasty were challenged in a recent study of 2,287 patients (2007 Annual Conference of the American College of Cardiology, New Orleans). All the patients had substantial blockage of the arteries, but were medically stable. All were treated with medication such as aspirin and beta-blockers. However, half the patients were randomly assigned to get an angioplasty and half were not. After five years, the researchers found that 211 of the 1,145 patients in the angioplasty group had subsequent heart attacks, compared with 202 of 1,142 patients in the medicationonly group. Do you agree with the study’s conclusion that “There was no significant difference in the rate of heart attacks for the two groups”? Support your answer with a 95% confidence interval.
Questions & Answers
QUESTION:
Problem 56E
Angioplasty’s benefits challenged. Each year, more than 1 million heart patients undergo an angioplasty. The benefits of an angioplasty were challenged in a recent study of 2,287 patients (2007 Annual Conference of the American College of Cardiology, New Orleans). All the patients had substantial blockage of the arteries, but were medically stable. All were treated with medication such as aspirin and beta-blockers. However, half the patients were randomly assigned to get an angioplasty and half were not. After five years, the researchers found that 211 of the 1,145 patients in the angioplasty group had subsequent heart attacks, compared with 202 of 1,142 patients in the medicationonly group. Do you agree with the study’s conclusion that “There was no significant difference in the rate of heart attacks for the two groups”? Support your answer with a 95% confidence interval.
ANSWER:
Step 1 of 3
The two samples represent independent binomial experiments. The binomial random
variables are the numbers
group and medication-only group respectively.
The results are summarized in the table above.
We now calculate the sample proportions 
group respectively.
