After reading the example above where one can see how probability values can be used in managerial decision-making to establish a product guarantee, post a comment where you think probability could be used to help solve other management-type questions/p

Read the steadfast muniment to see how answerance appraises are used by managers to fashion interest firmnesss. The unimpaired drift is worked out from rouse to end and should acceleration you in your computations in the item.


Unit 4

Practical Exercise



The subjoined illustration illustrates how answerance appraises using areas subordinate the rule recognized classification can be used to acceleration fashion interest firmnesss.




Let’s presume that the Goodyear Fatigue Community has true open a fatigue to be sold. Since the fatigue is new and Goodyear neglects to begin it into the consumer communicate, community executives respect that a mileage answer-for offered delay the fatigue earn be an considerable ingredient in buying the consequence. Goodyear managers neglect answerance knowledge environing the calculate of miles the fatigue earn latest.


From developed criterion grounds, Goodyear engineers price the average () fatigue mileage to be:


                                                            μ = 36,500 miles

                                                            σ = 5,000 miles


A.  What is the answerance that fatigue mileage earn abound 40,000 miles?


Step1.   At x = 40,000             .70


Step 2.  The area to the left of .70 (listed in Table V on page A-11 in the epilogue in your citation) is correspondent to .7580


Step 3. Subtract .7580 from 1.0 (the aggregate area subordinate the flexion is correspondent to 1.0)


1.0 - .7580 = .2420


24.20% of the fatigues earn abound 40,000 in mileage


B.  Let’s now affect that Goodyear is regarding a answer-for that earn supply a allowance on repossession fatigues if the pristine fatigues do not abound the mileage in the answer-for.  What should the answer-ford mileage be if Goodyear neglects no past than 10% of the fatigues to be choice for a allowance?


The knowledge we entertain beneficial lawful now to acceleration in this firmness is that we entertain a population average of 36,500 delay a rule sinuosity of 5,000. Goodyear conduct neglects no past than 10% of the fatigues to be choice for a allowance answer-for. If we entice a recognized classification flexion, 10% of the fatigues earn drop in the inferior left inferiority of the flexion.  Thus, we are looking for the z-score appraise, such that the area to the left of this z-score subordinate the rule recognized classification flexion is 10%, or 0.1000.  Since the appraise 0.1000 does not answer precisely in Table V, we use the closest appraise that is in the table, which is 0.1003.  It answers at the intersection of row -1.2 and column .08, which corresponds to the z-score of -1.28. 


To perceive the mileage of an hidden appraise of x that corresponds to a z = -1.28 we clear-up algebraically:


Follow each step:      

Method 1                                                      or       Method 2






     3.       30,100 = 36,500 – 1.28 (5,000)

 3.                 x = 30,100


Either system to clear-up for x works. Use the system you’re most agreeable delay.


A answer-for of 30,000 earn converge the condition that 10% of the fatigues earn be choice for the answer-for.


From this illustration, we can see how answerance can acceleration the firmness fashionr in reaching a good-tempered-tempered firmness.