CONDITIONAL PROBABILITY :

2. A laboratory technician is being tested on her ability to detect contaminated blood

samples. Among 100 samples given to her, 20 are contaminated, each with about the

same degree of contamination. Suppose the technician makes the correct decision 90% of

the time (both directions, positive and negative).

a. Make a two-way table showing what you would expect to happen.

b. Compute and interpret her PPV.

c. Compute and interpret her NPV.

d. How would these rates change if she were given 100 samples with 50 contaminated?