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Exercise 7.2

The cure rate for a the standard treatment of a disease is 45%. Dr. Snyder has perfected a primitive treatment which he claims is much better. As evidence, he says that he has used his new treatment on 50 patients with the disease and cured 25 of them. What do you think? Is this new treatment better. Use a 95% confidence interval to answer the question. (Ans.: (.36,.64)).
Experimenters injected a growth hormone gene into thousands of carp eggs. Of the 400 carp that grew from these eggs, 20 incorporated the gene into their DNA (Science News, May 20, 1989). Calculate a 95% confidence interval for the proportion of carp that would incorporate the gene into their DNA. From Statistics, S. Rasmussen, CA: Brooks/Cole, 1992. (Ans.: (.03,.07)).
Using Carrie's baseball data, estimate the proportion of professional baseball players who weigh 200 or more pounds. Find a 95% confidence interval for this proportion and interpret it. Recall Carrie's baseball card data set, Click here to see it . (Ans: 21 out of 59 weigh 200 or more pounds. So the CI is: (.23, .48)).