Stadistics

Nota:

• The science in charge of collecting, describe, analize and interpret data.

1. Basic Concepts
   1. Statistic
      1. Measure calculated to describe a characteristic of the population
   2. Parameter
      1. Measure calculated to describe a characteristic of the poblation
   3. Sample
      1. Piece of the whole population to analize
   4. Population
      1. All the elements in consideration
   5. Random Variables

      Nota:

      • Caracteristics of the data or information recolected
      1. Quantitative

         Nota:

         • Numerical
         1. Discrete
         2. Continous

            Nota:

            • To obtain it you need to measure it?????
      2. Qualitative

         Nota:

         • Non numerical (caracteristics)
2. Measurement Scales
   1. Nominal
      1. Identity property

         Nota:

         • X have magnitude Its values are truth X numerical value
   2. Ordinal
      1. Identity and magnitude properties

         Nota:

         • Stablish an order X quantifies the distance between the categories
   3. Interval
      1. Identity, magnitude and equal intervals properties

         Nota:

         • Allows negative values The 0 doesnt means the absence
   4. Ratio
      1. Identity, magnitude, equal intervals properties and an absolute cero

         Nota:

         • Has all the previous characteristics Do operations
3. Sampling Methods
   1. Probabilisticos
      1. Simple

         Nota:

         • Asignar un # Usar un medio para elegir la muestra
      2. Estratificado

         Nota:

         • niveles deacuerdo a la importancia
      3. Multistage
      4. Sistematico
   2. No probabilisticos
      1. Voluntario
      2. Conveniente
4. Visual Displays of data
   1. Distribucion de frequencias
      1. F absoluta

         Nota:

         • # de veces que ocurre algo
      2. F relativa

         Nota:

         • % de cada dato
      3. Distrubucion
         1. Cada dato pertenece (E) a una clase
         2. Datos Agrupados

            Nota:

            • Limite superior Limite inferior Ancho de clase Marca de clase
      4. Graphs
         1. Poligonal
         2. Circular / Pay
         3. Bars

            Nota:

            • barras
         4. Steam and leaves
         5. Histogram
5. Measures
   1. Central tendency
      1. Mean
         1. Mean is equal to the addition of all values/ the number of data
      2. Mode
         1. Most repited informarion

            Nota:

            • bi modal multimodal
      3. Median

         Nota:

         • X sensitive to extreme values changes Divides the groups of numbers in 2 parts
         1. Steps to find it

            Nota:

            • 1. Organize data fron lower to higher 2. Divide # in to parts by the half 3. Obtain median Par: (promedio de 2 centros)/ Impar: (dato en el centro)
      4. Weighted mean
         1. Weigted Mean is equal to de adition of all values * frequency / The adition of all frquencies
   2. Dispertion

      Nota:

      • How far are the data between 
      1. Coefficient of variation
         1. (s/X) x 100%

            Nota:

            • Division de medida por 100 Medicion relativa de la variacion
      2. Range
         1. R= Biggest value - Smallest value
      3. Chevyshev´s Theorem
         1. (1)-(1/(k*k))

            Nota:

            • % de info en cierto #
      4. Standart deviation

         Nota:

         • 1. Calcular Media 2.Calcular la desviacion media 3. Elevar al cuadrado la desviacion 4. Sumar las desviaciones 5. Dividir (entre n o n-1) 6. Sacar raiz  cuadrada FIN ;)
         1. sqrt((la suma de todos los datos - la media) alcuadrado/ (numero de datos [en caso de que sea muestral # de datos -1]))