Measures of Central Tendency /By Javier Nuñez
It is a single value that indicates the center of a series of numbers from which it is calculated.
Average or Centralization measure
Typical or representative value of a data set
When and how should we use the mean and median?
The answer will have to do with the data collected.
If the data is fairly homogeneous (as is the weight analysis), the average is used.
For example, what would happen if there were two people with weights greater than 100 kilos? In this case, the average would increase substantially and the conclusions derived from this analysis could be erroneous.
When using the median, the existence of two extreme data does not affect the final result.
In the use of the median two situations can occur:
1. If the sample size is an odd number, the median would be the data that separates the series into equal parts. To obtain this data, the formula is as follows: (n+1) / 2.
2. If the sample size is an even number, then the median will be the average value between the two data that divide the series.
Fashion
Central tendency measure. Value that occurs most often in a set of scores represented by Mo
The mode: classes and frequencies
The value that is repeated and the greatest number of times are sought, only that they are grouped into classes and the average of the class that contains the mode is used.
The mode for simple and frequency series:
Find the value that is repeated the greatest number of times in the series and without doing any calculations or formulas.
geometric mean
The geometric mean (Mg) is used in the calculation of the average rates of variation and in the elaboration of the index numbers.
The formula to use in the geometric mean is:
Mg = n√(x1) (x2) (x3),..., (xn)
harmonic mean
The harmonic mean (/via), of a series of n, numbers *i, x2, x3,..., xn,. It is defined as the reciprocal value of the arithmetic mean of the numbers.
Other Measures: Deciles, Quartiles and Percentiles
Arithmetic mean or mean
Also known as "average"
Measure of central tendency that an ordinary person has in mind and is represented by X
It is calculated by adding the values of the series where the average is obtained and the result is divided by the number of data that are the sum.
It is achieved in the following way:X=X1 + X2 + X3 + X4 + X5...+Xnn/ (number of elements in the series)
Also the arithmetic mean is calculated for frequency series and grouped data.
Median
It is the mean value of a data sequence.
Divide a set of ordered values into two equal groups
La mitad de los números tendrá valores que son menores que la mediana y la otra mitad alcanzará valores mayores y se representa por letras Md
Sort the values from highest to lowest or vice versa
Count to know if there is an even or odd number of values
Impar: La mediana es el valor central
Par: Promedio de los valores centrales
The position of the median is formulated: (n+1)/2 Value (it is obtained by finding the position of the median.