N.B. (that means Nota Bene or "good note" in Italian): You should use i.e. (id est or "that is" in Latin) here rather than e.g. (exempli gratia or "for example" in Latin).Originally Posted by ryanb118
a) If you add a data point to the set with value equal to the mean, you don't change the mean; however, "outliers" with values far away from the mean can skew it so much that it becomes useless.
b) This is not affected by outliers, but adding data points will in general disturb the median, and the median is not particularly useful if there are huge jumps in the data values close to it.
c) This is affected by neither outliers nor (in general) adding data points, but it can be VERY far from any reasonable notion of central tendency if there happen to be several outliers (say, of value 0) that affect the median little and the mean even less but whose value ends up being the mode.