- A10
- B11
- C8.1
- D9
Step-by-Step Solution
The mean stays 20. The sum of squared deviations stays , now shared among 10 values: . Adding a value at the mean lowers the variance.
Answer: D) 9
Nine observations have mean 20 and variance 10. A tenth observation equal to 20 is added. What is the new variance?
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