In mathematics and statistics the arithmetic average (or just average) a set of numbers is the sum of all numbers in this set divided into their quantity. The arithmetic average is the most general and most widespread concept of average size.
It is required to you
- Knowledge of mathematics.
Instruction
1. Let set of four numbers be given. It is necessary to find average value of this set. For this purpose at first we will find the sum of all these numbers. Let's allow these numbers 1, 3, 8, 7. Their sum is equal to S = 1 + 3 + 8 + 7 = 19. A set of numbers has to consist of numbers of one sign, otherwise the meaning in calculation of average value is lost.
2. The average value of set of numbers is equal to the sum of numbers S divided into quantity of these numbers. That is it turns out that the average value is equal: 19/4 = 4.75.
3. For set number it is also possible to find not only an arithmetic average, but also an average geometrical. An average of geometrical several positive real numbers is called such number with which it is possible to replace each of these numbers so that their work did not change. Average geometrical G is looked for on a formula: the degree root N-oh from performing enrollment of numbers where N is quantity number in set. Let's consider the same set of numbers: 1, 3, 8, 7. Let's find their average geometrical. For this purpose we will count the work: 1*3*8*7 = 168. Now it is necessary to take a root of the 4th degree from number 168: G = (168) ^1/4 = 3.61. Thus the average geometrical a set of numbers is equal to 3.61.