A study was conducted among 2,188 patients who were evaluated at autopsy for the presence of Alzheimer's Disease (AD) or other forms of dementia (Other) by previously established pathological criteria. Patients were also evaluated clinically for the presence of AD.

PATHOLOGICAL DIAGNOSIS

CLINICAL DIAGNOSIS AD Other Total

AD 1643 190 1833

Other 127 228 355

Total 1770 418 2188

1. If the clinical diagnosis is considered a screening test for Alzheimer's Disease and the disease status is given by the pathological diagnosis, what is the sensitivity of this test?Which is the correct answer? There may be slight rounding differences. Please provide an explanation.

a. 0.928

b. 0.982

c. 0.829

d. 0.289

2.What is the specificity of this test? Which is the correct answer? There may be slight rounding differences. Please provide an explanation.

a. 0.617

b. 0.906

c. 0.716

d. 0.545

3. According to this sample, what is the probability that a person has Alzheimer Disease according to both pathological diagnosis and clinical diagnosis?Which is the correct answer? There may be slight rounding differences. Please provide an explanation.

a. 0.517

b. 0.751

c. 0.157

d. 0.001