medium · GMAT Quant
A quality control engineer monitors component weights across two manufacturing lines, Line A and Line B. Both lines produce components with an identical mean weight of 50.0 grams. Line A analyzed 12 components with a population variance of 15.0, while Line B analyzed 8 components with a population variance of 30.0.
What is the combined population variance of the component weights across all 20 components?
- 18.0
- 21.0
- 22.5
- 45.0
- 420.0
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