In mathematics and statistics, the<unk>  (or simply the<unk>  of a list of numbers is the sum of all the members of the list divided by the number of items in the list.  The<unk>  is what students are taught very early to call the "average". If the list is a statistical population, then the<unk>  of that population is called a population<unk> . If the list is a statistical sample, we call the resulting statistic a sample<unk> .
When the<unk>  is not an accurate estimate of the median, the list of numbers, or frequency distribution, is said to be skewed.
Arithmetic mean
Median
Average
Quantum yield
Ancillary statistic
Absolute deviation
P-value
Extraction ratio