Rothenberg et al. (A-13) investigated the effectiveness of using the Hologic Sahara Sonometer, a portable device that measures bone mineral density (BMD) in the ankle, in predicting a fracture. They used a Hologic estimated bone mineral density value of .57 as a cutoff. The results of the investigation yielded the following data:

Confirmed Fracture Present (D) Not Present ð Þ D Total BMD ¼ :57ðTÞ 214 670 884 BMD > :57ðTÞ 73 330 403 Total 287 1000 1287 Source: Data provided courtesy of Ralph J. Rothenberg, M.D., Joan L. Boyd, Ph.D., and John P. Holcomb, Ph.D.

(a) Calculate the sensitivity of using a BMD value of .57 as a cutoff value for predicting fracture and interpret your results.

(b) Calculate the specificity of using a BMD value of .57 as a cutoff value for predicting fracture and interpret your results.