Problem 2) The life length of semiconductor lasers is normally distributed with

Question

Problem 2) The life length of semiconductor lasers is normally distributed with a mean of 7000 hours and a standard deviation of 500 hours. a) (7 points) What is the probability that the life length of a randomly chosen laser is less than 6000 hours? Round your answer to four decimal places). r(6000-lee f(-2) . 022% b) (8 points) If 4 lasers are randomly selected, independent of each other, what is the probability that at least one of these 4 lasers has life lengthexceeding 7000 hours? (Round your answer to four decimal) places)

Explanation / Answer

b) Since mean = 7000 hours

P(X < 7000) = P(X > 7000) = 0.50

Given that all the 4 lasers are independent of each other. Hence,

P(At least one has life length exceeding 7000 hours)

= 1 - P(None has life length exceeding 7000 hours)

= 1 - (0.5)4

= 0.9375

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

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