# Probability: Failures, Least Amounts and Joint Probability

1. There are five computers in an office. The probability of failure of a computer is 0.3. What is the probability that (a) there are 3 computers working, and (b) at least three computers working?

2. A computer service company is interested in the number of computers that fail. There are hundreds of computers in use in their service area. The probability of failure of a computer is 0.08. What is the probability that (a) there are 4 failures, and (b) no failure?

3. Flight time between points A and B is normally distributed with mean of 5 hours and a standard deviation of 2.5 hours. What is the probability that a given flight will take more than 7 hours?

9. The joint probability mass function of X and Y, p(x, y), is given by

p(1,1)= , p(2,1)= , p(3,1)= ,

p(1,2)= , p(2,2)=0, p(3,2)= ,

p(1,3)=0, p(2,3)= , p(3,3)=

Compute for 1, 2, 3.

https://brainmass.com/statistics/probability/probability-failures-least-amounts-joint-probability-227197

#### Solution Summary

This solution contains step-by-step calculations to determine the probability of failures, least amounts and joint probability of mass transfer function. All workings and equations are shown.