medium · GMAT Quant
A retail chain measures customer satisfaction scores across three store branches. Store 1 has 5 responses with a mean of 70 and mathrmSSW_1 = 50. Store 2 has 5 responses with a mean of 90 and mathrmSSW_2 = 70. Store 3 has 10 responses with a mean of 80 and mathrmSSW_3 = 80.
What is the total sum of squares (mathrmSST) for the combined data set of 20 responses?
- 200
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- 1250
- 1400
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