medium · GMAT Quant
A quality control engineer at a semiconductor plant measures clock speed deviation across two manufacturing batches with identical mean clock speeds. Batch A consists of 11 microprocessors (n_1 = 11) with a sample variance s_1^2 = 16 MHz^2. Batch B consists of 21 microprocessors (n_2 = 21) with a sample variance s_2^2 = 34 MHz^2.
What is the combined pooled sample variance s_p^2 across both batches?
- 28 MHz^2
- 25 MHz^2
- 26.25 MHz^2
- 840 MHz^2
- 27.81 MHz^2
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