Homework Sourse1114 Refer to the table which summarizes the results of test
#11-14: Refer to the table which summarizes the results of testing for a certain, relatively hard to detect, but not very rare, disease.
Positive Test Result ()
Negative Test Result ()
Total
Person has the disease (D)
32
28
60
Person does not have the disease (ND)
8
232
240
Total
40
260
300
11) What percent of all of the participants have the disease (Pr (D))?
12) If one of the results is randomly selected, what is the probability that it is a false positive (test indicates a positive result when, in fact, the person tested does not have the disease; in other terms, Pr (/ND))?
13) What is the miss rate of this test? That is, what is the probability that the test indicates a negative result when the person tested does not actually have the disease (Pr (/D))?
14) What is the Positive Predictive Value of this test? That is, what is the probability that a person has the disease given the test result was positive (Pr (D/))?
| Positive Test Result () | Negative Test Result () | Total | |
| Person has the disease (D) | 32 | 28 | 60 |
| Person does not have the disease (ND) | 8 | 232 | 240 |
| Total | 40 | 260 | 300 |
Solution
11.
P(D) = 60/300 = 0.2 [ANSWER]
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12.
P(+|ND) = 8/40 = 0.2 [ANSWER]
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13.
P(-|D) = 28/60 = 0.466666667 [ANSWER]
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14.
P(D|+) = 32/40 = 0.8 [ANSWER]
