Defective CDs

A manufacturer of CDs has two plants. Last month one plant made 156,429 CDs, of which 4,280 were defective. At the other plant, 2-1/2 percent of the 325,143 CDs made last month were defective. Which plant did better?


The percent at the first plant is about 2.74% That's better than the 2-1/2 percent at the second plant. So the first plant is doing better. The 325,143 is irrelevant.


The 325,143 is relevant. 2-1/2 percent of 325,143 is more than 4280, so the first plant is doing better.


325,143 is relevant, but not for that reason. The higher percent of a larger volume is expected.




savings from buying in quantity, more efficiency in larger plant may compensate for larger rate of defects. What do we mean by "better"?


Your experience

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Last updated 30 November, 2004