Concept:The arithmetic mean is a measure of central tendency easily distorted by extreme values.
Explanation:The arithmetic mean is calculated by adding all values and dividing by the number of values.
Because every value is included in the calculation, a very high or very low extreme value pulls the mean toward it.
This makes the mean less representative of the typical value in data that contains outliers.
For example, in the data set
2,3,4,100, the mean is
42+3+4+100=27.25, which is not close to most values.
Therefore, the arithmetic mean is not reliable when extreme data are present.
Answer:D. affected by extreme data