hard · GMAT Quant
An operations researcher recorded daily assembly times for two factory units. Unit A operated for 5 days with a sample variance of 16 square minutes per day (using n - 1). Unit B operated for 10 days with a population variance of 18 square minutes per day (using n). Given that both units had the same mean assembly time
What is the population variance, in square minutes per day, for all 15 operating days combined?
- dfrac26015
- dfrac24414
- dfrac24415
- dfrac22615
- 17
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