- A4
- B3.46
- C3.74
- D3
Step-by-Step Solution
Two numbers with mean 9 and SD 3 are : 6 and 12. With 15 the mean is 11, squared deviations 25, 1, 16 add to 42. Variance , SD .
Answer: C) 3.74
Two numbers have mean 9 and standard deviation 3. A third number, 15, is added to them. Find the standard deviation of the three numbers.
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