medium · GMAT Quant
Line 1 has 16 unit weights with mean 40 and standard deviation 8. Line 2 has 24 unit weights with mean 60 and standard deviation 12.
Treating each standard deviation as the population root-mean-square deviation from its group mean, what is the combined population standard deviation of all 40 observations?
- 10.00
- 10.40
- 708.35
- 14.42
- 20.00
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