Twenty-three concrete blocks were sampled and tested for crushing strength in order to estimate the proportion that were sufficiently strong for a certain application. Eighteen of the 23 blocks were sufficiently strong. Use the small-sample method to construct a 95% confidence interval for the proportion of blocks that are sufficiently strong
A)(0.575, 0.906)
B)(0.614, 0.951)
C)(0.562, 0.920)
D)(0.602, 0.879)

Question

Quizplus · Accepted Answer

The correct answer is A because the 95% confidence interval for the proportion of blocks that are sufficiently strong is (0.575, 0.906). This interval was calculated using the small-sample method, which is appropriate when the sample size is less than 30.

Twenty-Three Concrete Blocks Were Sampled and Tested for Crushing Strength