medium · GMAT Quant
A retail conglomerate measures daily customer spending across two regional divisions with identical mean spending per customer. Division 1 surveyed N_1 = 40 transactions with a population variance of σ_1^2 = 100. Division 2 surveyed N_2 = 60 transactions with a population variance of σ_2^2 = 225.
What is the population standard deviation σ of the combined dataset of 100 transactions?
- 5√(7)
- 175
- 12.5
- dfrac5√(26)2
- dfrac50√(7)3√(11)
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