Question

An article in Knee Surgery, Sports Traumatology, Arthroscopy (2005, Vol. 13, pp. 273–279) “Arthroscopic meniscal repair with an absorbable screw: results and surgical technique” showed that only 25 out of 37 tears (67.6%) located between 3 and 6 mm from the meniscus rim were healed.

(a) Calculate a 99% two-sided confidence interval on the proportion of such tears that will heal. Round the answers to 3 decimal places.

(b) Calculate a 99% lower confidence bound on the proportion of such tears that will heal. Round the answer to 3 decimal places.

Answer 1

(a)

(b)

To calculate lower bound we need to use critical value that has 0.01 area to its left. The z-score -2.33 has 0.01 area to its left. So required lower bound is

Answer: 0.496