hard · GMAT Quantitative Reasoning
Shift A has 20 hourly output scores with mean 100 and standard deviation 15. Shift B has 30 hourly output scores with mean 80 and standard deviation 10.
Treating each standard deviation as the population root-mean-square deviation from its group mean, what is the combined population standard deviation of all 50 observations?
- 12.00
- 15.68
- 1060.66
- 12.50
- 20.00
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