Problem-Solving and Data AnalysisHardSeventh value that raises a mean
Problem-Solving and Data Analysis practice question
A data set of 6 values has a mean of 20. When a seventh value is added, the mean of the 7 values is 22. What is the seventh value?
Answer: 34
The six values sum to 120 and the seven to 154, so the seventh value is 34.
Common wrong answers
- If you answered 2
- 2 is the change in the mean, not the value.
- If you answered 22
- 22 assumes the new value equals the new mean.
- If you answered 32
- 32 uses 6 × 22 − 120 = 12 and then miscounts.
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