SAT Math Multiple Choice Question 772: Answer and Explanation
A researcher is studying the effectiveness of a method for testing the presence of an antibody in a patient's bloodstream. The table above shows the results of 1,000 patient trials. According to these data, what is the probability that a patient who has the antibody will nevertheless have a negative test result?
- A. 0.01
- B. 0.04
- C. 0.05
- D. 0.20
Correct Answer: B
Problem Solving and Data Analysis (quadratics) MEDIUM
The table indicates that a total 500 patients had the antibody and that 20 of these patients nevertheless had a negative test result. Therefore the probability of this result is 20/500 = 0.04.