# Question

An operator needs to produce 4 pins and 6 shafts using a lathe which has 72% chance of producing a defect-free pin at each trial and 65% chance of producing a defect-free shaft at each trial. The operator will first produce pins one by one until he has 4 defect-free pins and then produce shafts one by one until he has 6 defect-free shafts.

a. What is the expected value and variance of the total number of trials that the operator will make?

b. Suppose each trial for pins takes 12 minutes and each trial for shafts takes 25 minutes. What is the expected value and variance of the total time required?

a. What is the expected value and variance of the total number of trials that the operator will make?

b. Suppose each trial for pins takes 12 minutes and each trial for shafts takes 25 minutes. What is the expected value and variance of the total time required?

## Answer to relevant Questions

Hedge funds are institutions that invest in a wide variety of instruments, from stocks and bonds to commodities and real estate. One of the reasons for the success of this industry is that it manages expected return and risk ...Find two values, equidistant from 0 on either side, such that the probability that a standard normal random variable will be between them is 0.40. A normal random variable has mean 0 and standard deviation 4. Find the probability that the random variable will be above 2.5. Based on the research of Ibbotson Associates, a Chicago investment firm, and Prof. Jeremy Siegel of the Wharton School of the University of Pennsylvania, the average return on large-company stocks since 1920 has been 10.5% ...If X is a normally distributed random variable with mean 97 and standard deviation 10, find x2 such that P(102 < X < x2) = 0.05.Post your question

0