Find the indicated probability. Round to four decimal places.
-In one city, the probability that a person will pass his or her driving test on the first attempt is 0.63 11 people are selected at random from among those taking their driving test for the first time. What Is the probability that among these 11 people, the number passing the test is between 2 and 4
Inclusive?
A)0.0667
B)0.0742
C)0.0638
D)0.0522

Question

Find the indicated probability. Round to four decimal places.
-In one city, the probability that a person will pass his or her driving test on the first attempt is 0.63 11 people are selected at random from among those taking their driving test for the first time. What Is the probability that among these 11 people, the number passing the test is between 2 and 4
Inclusive? 
A)0.0667
B)0.0742
C)0.0638
D)0.0522

Quizplus · Accepted Answer

The probability of passing the test is 0.63, and the probability of failing the test is 0.37. The probability of getting between 2 and 4 people passing the test is the sum of the probabilities of getting 2, 3, or 4 people passing the test. The probability of getting 2 people passing the test is (11 choose 2) * (0.63)^2 * (0.37)^9 = 0.0667. The probability of getting 3 people passing the test is (11 choose 3) * (0.63)^3 * (0.37)^8 = 0.0075. The probability of getting 4 people passing the test is (11 choose 4) * (0.63)^4 * (0.37)^7 = 0.0001. The sum of these probabilities is 0.0667 + 0.0075 + 0.0001 = 0.0742.

Find the Indicated Probability