1. It is known that events A and B are joint and independent P(B)-8P(A), P(A+B)-

Question

1. It is known that events A and B are joint and independent P(B)-8P(A), P(A+B)-1/8. Find P(A). 2. Consider a hospital serving 100,000 people. Further consider an illness X; the probability for a human to become infected with X within a year is 0.000035. What is the probability that more than 3 people at this hospital catch X in each year? 3. 12 students are trying to pass the exam that consists of 25 question cards and each student is required to answer one of them chosen at random. 4 students know answers to 20 question cards and aren't able to answer the rest 5; two students did not put enough effort into preparation and know answers to only 8 question cards; the other students know answers to all question cards. What is the probability that a student chosen at random from these 12 students will pass the exam, if the probability to pass the exam is 0.9 if the student knows the answer to the question cards he/she gets and O otherwise?

Explanation / Answer

Question 1

P(B) = 8 P(A)

P(A + B) = 1/8

P(A + B) = P(A) P(B) = 1/8

P(A) * 8 P(A) = 1/8

P(A)2 = 1/64

P(A) = 1/8

question 2

Here Pr(Infected) = 0.000035

Expected number of people who catch x in each year = 100,000 * 0.000035 = 3.5

if x is the number of hosptial catch x in each year.

Pr(X > 3) = 1 - POISSON (x =< 3 ; 3.5)

= 1 - 0.5366

= 0.4634

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

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