Home › Bihar Board Class 12 (Commerce) › Mathematics › Probability › 1% are ill; test is + for 90% of ill, 5% of heal…
1% are ill; test is + for 90% of ill, 5% of healthy. P(ill | +)?
A9/10
B1/20
C2/13
D9/100
Answer & Solution
Correct answer: C. 2/13
P(ill|+) = 0.009 / (0.009 + 0.0495) = 0.009/0.0585 = 2/13, small because healthy people vastly outnumber the ill.
Related questions
If P(A) = 0.6 and P(B) = 0.7, the smallest possible P(A and B) isA bag has 5 red, 3 green and 2 yellow marbles. P(red or yellow) isTwo dice are thrown. P(first die is 6 and sum is at least 11) isA card is drawn from ten cards numbered 1 to 10. P(2, 4, 6 or 8) isTwo fair dice are thrown. P(sum greater than 11) isTwo fair coins are tossed. P(exactly one head) isA fair die is rolled. P(a number less than 3) isIn P(A) + P(B), the sample points of A and B together are counted