In addition to standard exercise electrocardiography (SEE), two widely applied methods of stress testing of cardiac patients are stress echocardiography (SE) and single-photon emission computed tomography (SPECT). These methods were evaluated in the American Journal of Medical Quality (Mar./Apr. 2014). A sample of 866 heart catheterization patients in the Penn State Hershey Medical Center all received some form of stress testing prior to the catheterization. Of these, SE was performed on 272 patients, SPECT on 560 patients, and SEE on 38 patients. Four patients received both SE and SPECT but not SEE. Consider a patient randomly selected from those in the study.

a. What is the probability that the patient received SE prior to the catheterization?

b. What is the probability that the patient received both SE and SPECT prior to the catheterization?

c. Given that the patient received SPECT, what is the probability the patient also received SE prior to the catheterization?