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Statistics

1. Basic Concepts

   • Poputation
     • All of the items.  PARAMETER 
   • Sample
     • Part of the population.  STATISTICS 
   • Variable
     • Quantitative
       • Continous
         • Decimal Numbers. 
       • Discrete
         • Rounded Numbers.
     • Qualitative
       • Can´t count it. 

2. Measurement Scales

   • Properties
     • Identity
       • Unique meaning. 
     • Magnitude
       • Values larger and some smaller. 
     • Equal Intervals
       • Equal to each one another. 
     • Value of zero
       • True zero point, no values exist below. 
   • Nominal
     • No more or less. EX= gender, religion.  IDENTITY 
   • Ordinal
     • Identity and magnitude. EX: a horse race.
   • Intervals
     • Identity, magnitude and equal intervals. EX: scale to measure temperature. 
   • Ratio Scale
     • Identity, magnitude, equal intervals, and a minimum value of zero. EX: weight    

3. Sampling Methods

   • Probability
     • Simple random
       • All samples can occur.  Lottery 
     • Stratified random
       • Population divided in to groups called strata.  Nacional survey states.
     • Cluster
       • One and only group. Sample includes elements only from clusters. 
     • Multistage
       • Two or more sampling methods. 
     • Systematic Random
       • List of population randomly selected.  "Encuesta de satisfaccion" 
   • Non probability
     • Voluntary
       • May be interested in the survey topic. 
     • Convenience
       • Easy to reach 

4. Visual Displays of Data

   • Displays
     • Histogram
     • Stem and leaf
     • Bar Graphs
     • Circle graphs
     • Linear Graphs

5. Measures

   • Central Tendency
     • MEAN
     • Median
     • Mode
   • Dispresions
     • Coefficient of variation
       • V= S/X* 100
     • Chevyshev´s Terorem
       • 1 - 1/K2
     • Range
       • Greatest value - lower value 
     • Standar deviations
       • S= E (X1-X2) 2 / N-1
   • Position
     • Percentile
       • number by number  P14
     • Decile
       • 10 by 10 
     • Quartile
       • Q1= 25  Q2= 50  Q3= 75