medium · GMAT Quant
A customer support center analyzes call handling times across two shifts that have identical average handling times. The morning shift records n_1 = 20 calls with a population variance of σ_1^2 = 9 square minutes. The evening shift records n_2 = 30 calls with a population variance of σ_2^2 = 16 square minutes.
What is the combined population variance of call handling times across all 50 calls?
- 12.5
- 13.2
- 14.5
- 660.0
- 13.75
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