Statistics

Statistics

1. Measures of central tendency

   • If a data set is ordered in ascending or descending order, any measure that this located in the center of such a set is called a measure of central tendency.
   • The geometric mean
     • The geometric mean (Mg) is used in the calculation of the average rates of variation and in the elaboration of index numbers.
       • The formula to use in the geometric mean is: Mg=n√((x1)(x2)(x3),…,(xn))
   • 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 dividing the result by the number of data that are the sum.
     • It is obtained as follows: 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
   • Mode
     • Measure of central tendency, value that is repeated with greater frequency 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 are uses the average of the class that contains the mode.
     • The mode for simple series and frequencies
       • Find the value that is repeated the greatest number of times in the series and without doing any calculation or form.
   • Median
     • It is the mean value of a sequence of data
     • Splits a set of sorted values into two groups same
       • Half of the numbers will have values that are less than the median and the other half will reach higher values and is represented by letters Md.
     • Ranks the values of greater or lesser and vice versa
     • Count to know if there is an even number or odd
       • Odd: The median is the value central.
       • Par: Average of the central values.
     • The position of the median is formulated: (n+1)/2
       • Value (Obtained by finding the position of the median)

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