A certain affects virus 0.8% of the population. A test used to detect the virus

Question

A certain affects virus 0.8% of the population. A test used to detect the virus in a person is positive 85% of the time if the person has the virus (true positive) and 14% of the time if the person does not have the virus (false postive). Fill out the remainder of the following table and use it to answer the two questions below.

a) Find the probability that a person has the virus given that they have tested positive. Round your answer to the nearest tenth of a percent and do not include a percent sign.
P(Infected | Positive Test) = %

b) Find the probability that a person does not have the virus given that they test negative. Round your answer to the nearest tenth of a percent and do not include a percent sign.
P(Not Infected | Negative Test) = %

Infected Not Infected Total Positive Test Negative Test Total 800 99,200 100,000

Explanation / Answer

Completed table will be:

Hence,

a) P(Infected | Positive test)

= 680 / 14568

= 4.7%

b) P(Not infected | Negative test)

= 85312 / 85432

= 99.9%

Infected Not Infected Total Positive Test 800*0.85 = 680 99200*0.14 = 13888 14568 Negative Test 800*0.15 = 120 99200*0.86 = 85312 85432 Total 800 99200 100000

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.