21.5 Exercises
Selected answers are available in Sect. D.20.
Exercise 21.1 A researcher was computing a 95% CI for a single proportion to estimate the proportion of trees with apple scabe (Hirst and Stedman 1962), and found that \(\hat{p} = 0.314\) and \(\text{s.e.}(\hat{p}) = 0.091\).
What is wrong with the following conclusion that the researcher made?
The approximate 95% CI for the sample proportion is between 0.223 and 0.405.
Exercise 21.2 A researcher was computing a 95% CI for a single proportion to estimate the proportion of trees with apple scabe (Hirst and Stedman 1962), and found that \(\hat{p} = 0.314\) and \(\text{s.e.}(\hat{p}) = 0.091\).
What is wrong with the following conclusion that the researcher made?
This CI means we are 95% confident that between 22.3 and 40.5 trees are infected with apple scab.