A data set has 10 values with a mean of 50. If each value in the data set is increased by 20%, what is the new mean?
- 50
- 60 (correct answer)
- 70
- 55
Explanation: When each value in a data set is multiplied by the same constant, the mean is also multiplied by that constant. Increasing each value by 20% means multiplying by 1.20. Therefore, the new mean is 50 × 1.20 = 60. Choice A incorrectly assumes the mean stays the same. Choice C adds 20 instead of multiplying by 1.20. Choice D adds 10% instead of 20% to the mean.