A data set has mean 5 and standard deviation 2. Every value is multiplied by 3. What are the new mean and standard deviation?
Answer and explanation
Correct answer: D. Mean 15, standard deviation 6
- Step 1: Multiplying every value by 3 multiplies the mean by 3: . Step 2. It also multiplies the spread by 3: . Answer: Mean 15, standard deviation 6. Why not the others: Standard deviation 2 is what happens when 3 is added, not multiplied, a mean of 5 ignores the scaling of the values, and 18 multiplies the standard deviation by 9, which is what happens to the variance.
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