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Proposal Number Sense Interactive Quiz Lesson Plans History Problem Bank Glossary Quotes Helpful Links References
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Mathematics Teacher, Vol. 92, No. 4, April 1999, p. 307 PT: Measures of Dispersion RW: Computer Company Consultant Professor Smith was hired as a consultant by the Atlas Computer Company. The company manufactures computers with three-year warranties; that is, Atlas will replace or repair any computer that fails within the warranty period. The supplier of the chip that is the main component of each computer was supplier X. Only 3% of Atlas’ Computers did not last through the warranty period. Supplier Y also wished to be the exclusive chip supplier. Professor Smith told the buyer to take a random sample of ten chips from each supplier and calculate the mean life of each supplier’s chips. The buyer informed the professor that the chips manufactured by supplier X have an average life of ten years, and the average life of the chips manufactured by supplier Y is twenty years. Professor Smith ordered the buyer to stop purchasing chips from supplier X and switch to supplier Y. After switching to supplier Y, the Atlas company computers began failing at an enormous rate. More than 50% of the computers failed during the warranty period, and the company was about to declare bankruptcy. Professor Smith is blamed for switching to a new supplier. He claims that the new supplier’s chips have an average life that is twice that of the old supplier. He offers no additional consulting to discover the problem. Atlas Computer Company looks for a new consultant to explain this situation. You are chosen as the new consultant. a) Can you give an explanation for both the average life of the new chips and the old and new failure rate? Here is the original data for supplier X chips, n = 10: 10, 10, 10, 10, 9, 11, 10, 11, 9, 10 Here is the original data for supplier Y chips, n = 20: 40, 2, 37, 1, 0, 31, 49, 1, 38, 1 (Hint: look at the mean, range, and standard deviation) b) How could Professor Smith use the data to find the probability of
failed chips before switching completely over to supplier Y? Key to Problem Bank:
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