2-by-2 contingency table to determine the total number of people who fail the diagnostic test, which represents the target market for hearing aid sales. A total of 487 people tested positive for hearing loss and will be referred for follow-up diagnostic testing. Given that the clinic-based audiology equipment for follow-up diagnostic testing has a 99% Sensitivity and 99% specificity, the number of people who are true positive of loss of hearing disease (a), false positive of the disease (b), false negative of the disease (c), and true negative of the disease (d) is calculated as follows: Test Result Disease Present (D) No Disease (NoD) Total Positive (a) 401 (b) 1 (a + b) 402 Negative (c) 4 (d) 81 (c + d) 85 Total (a + c) 405 (b + d) 82 (a + b + c + d) 487

2-by-2 contingency table to determine the total number of people who fail the diagnostic test, which represents the target market for hearing aid sales. A total of 487 people tested positive for hearing loss and will be referred for follow-up diagnostic testing. Given that the clinic-based audiology equipment for follow-up diagnostic testing has a 99% Sensitivity and 99% specificity, the number of people who are true positive of loss of hearing disease (a), false positive of the disease (b), false negative of the disease (c), and true negative of the disease (d) is calculated as follows: Test Result Disease Present (D) No Disease (NoD) Total Positive (a) 401 (b) 1 (a + b) 402 Negative (c) 4 (d) 81 (c + d) 85 Total (a + c) 405 (b + d) 82 (a + b + c + d) 487