Question

    Two data sets of sizes 6 and 9 have standard deviation

    3 and 4, respectively, and arithmetic means 4 and 4, respectively. The standard deviation of combined data set of size 15 is:
    A √(72/5) Correct Answer Incorrect Answer
    B √(68/5) Correct Answer Incorrect Answer
    C √(70/5) Correct Answer Incorrect Answer
    D √(66/5) Correct Answer Incorrect Answer

    Solution

    The correct answer is D

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