Thats just a fancy way to say the sum of k different numbers divided by k Check out a few examples of the arithmetic mean to make sure you understand. Average Sum of heights of malestotal number of males. Average Velocity is defined as the total displacement travelled by the body in time t.
Different concepts of average are used in different contexts.
In probability theory a probability density function PDF or density of a continuous random variable is a function whose value at any given sample or point in the sample space the set of possible values taken by the random variable can be interpreted as providing a relative likelihood that the value of the random variable would equal that sample. For example the expression SUMMETRICS returns a time series TS that is the sum of the values of all the graphed metrics. 9 3 7 3 8 10 and 2. A mathematical expression can be as simple as 2 4 or as complex as -4xy 8x- 5xy.