You will need
- Knowledge of math.
Suppose that we are given a set of four numbers. Need to find average value of this set. To do this, first find the sum of all these numbers. Let's say the numbers 1, 3, 8, 7. Their sum is equal to S = 1 + 3 + 8 + 7 = 19. A set of numbers must consist of numbers of the same sign, otherwise the point in calculating the average value is lost.
The average value of a set of numbers equal to the sum of the numbers S, divided by the number of these numbers. That is, the average value is equal to 19/4 = 4.75.
To set the number also can be found not only higher arithmetic, but also the mean geometric. Several geometric average of positive real numbers is called a number to replace each of these numbers so that their product has not changed. The geometric mean G is searched according to the formula: the nth root of the degree of the product of the set of numbers, where N is the number of numbers in the set. Consider the same set of numbers: 1, 3, 8, 7. Find their average geometric. To do this, calculate the work: 1*3*8*7 = 168. Now from among the 168 you must remove the root of the 4th degree: G = (168)^1/4 = 3.61. Thus the average geometric set of numbers is equal to 3.61.
The average value can not be greater than the largest number in the set and smaller than the small.
In mathematical statistics the mean value is a mathematical expectation.
Advice 2: How to find the geometric mean
The average geometric in General is used less frequently than the arithmetic mean, but it can be useful when calculating the average value of indicators changes over time (wages of an individual employee, the dynamics of indicators of progress, etc.).
You will need
- Scientific calculator
In order to find the geometric mean of several numbers, first you need to multiply all these numbers. For example, you are given a set of five indicators: 12, 3, 6, 9 and 4. Multiply all these numbers: 12х3х6х9х4=7776.
Now from the resulting numbers need to extract the root degree equal to the number of elements of the series. In our case, the number 7776 will need to extract the fifth root using the scientific calculator. Obtained after this operation the number – in this case 6 – will be the geometric average for source group number.
If you don't have the scientific calculator, then calculate the geometric mean of series of numbers by using functions SRGEON in Excel or by using one of the online calculators specifically designed to compute geometric means.
If you need to find the geometric mean of the total for the two numbers, the calculator you do not need to remove the root of the second degree (square root) of any number you can use the regular calculator.
Unlike the arithmetic mean, the geometric mean is not so much affected by large deviations and fluctuations between individual values in the test set.
Advice 3: How to calculate arithmetic mean
The average value is one of the characteristics of a set of numbers. Is a number that cannot go beyond the range defined by the largest and smallest values in this set of numbers. The average arithmetic value is the most commonly used kind of average.
Add up all numbers and divide them by the number of terms to obtain the arithmetic mean. Depending on the specific conditions of calculations it is sometimes easier to divide each number by the number of a data set and sum the result.
Use, for example, included in the Windows calculator, if you calculate the average arithmetic value in mind is not possible. You can open it using run dialog programs. To do this, press the "hot keys" WIN + R or click start and select in the main menu the command "Run". Then type in the input box and press calc on the keypad Enter or click "OK". The same can be done via main menu - open it, go to "All programs" and in "Standard" and select "Calculator".
Enter the sequence number of the set, clicking on the keyboard after each one (except the last) the "Plus" key or by clicking the appropriate button in the calculator interface. To enter the numbers too as you can with the keyboard or clicking the appropriate button interface.
Press the slash (slash), or click the icon in the interface of the calculator after entering the last value sets and print the number of numbers in the sequence. Then press the equal sign and the calculator will calculate and display the arithmetic mean value.
It is possible for this purpose to use the table editor Microsoft Excel. In this case, run the editor and enter in the adjacent cell all values of the sequence numbers. If after entering each number, you press Enter or the down arrow key or the right, the editor will move the input focus into the next cell.
Select all entries and in the lower left corner of the editor window (in the status) will see the average value for the selected cells.
Click the following for the last entered number cell, if you do not enough only to see the arithmetical mean value. Open the drop-down list with the image of the Greek letter Sigma (Σ) in the group of commands "Edit" on the Home tab. Select the line "Average" and the editor will insert the correct formula to calculate the arithmetic mean of the values in the selected cell. Press Enter and the value will be calculated.