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Two samples are combined. The first sample contains 100 observations with mean 15 and standard deviation 3. If the combined set has 250 observations with mean 15.6 and standard deviation √13.44, what is the standard deviation of the second sample?
- 5
- 4
- 6
- 3.52
Correct answer: 4
Solution
The standard deviation of the combined samples can be calculated using the formula that incorporates the means and standard deviations of both samples. Given the means and the overall standard deviation, we can derive the standard deviation of the second sample, which turns out to be 4.
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