Armco, a manufacturer of traffic light systems, found that | StudySoup

Textbook Solutions for Basic Statistics for Business and Economics

Chapter 5 Problem 47E

Question

Problem 47E

Armco, a manufacturer of traffic light systems, found that under accelerated-life tests, 95 percent of the newly developed systems lasted 3 years before failing to change signals properly.

a. If a city purchased four of these systems, what is the probability all four systems would operate properly for at least 3 years?

b. Which rule of probability does this illustrate?

c. Using letters to represent the four systems, write an equation to show how you arrived at the answer to part (a).

Solution

Solution :

Step 1 of 3:

Given a 95 percent of the newly developed systems lasted 3 years before failing to change signals properly.

Our goal is:

a). We need to find the probability of all 4 systems would operate properly for at least 3 years.

b). We need to find concept of probability does this illustrate.

c). We need to write an equation.

a). Then the probability of all 4 systems would operate properly for at least 3 years is

P =  

P = 0.8145

Therefore, the probability of all 4 systems would operate properly for at least 3 years is 0.8145.


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full solution

Title Basic Statistics for Business and Economics  7 
Author Douglas Lind; William Marchal; Samuel Wathen
ISBN 9780077384470

Armco, a manufacturer of traffic light systems, found that

Chapter 5 textbook questions

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