Statistics project

Statistics project

1. Definitions

   • Population: ALL the things
     • Sample: Part of the population
   • Quantitative variables
     • Measurable
       • Scales
         • Interval
           • Values that don't have an specific value in respect to 0
         • Ratio
           • Values countable from 0
   • Qualitative variables
     • Unmesurable
       • Scales
         • Nominal
           • Has identities
         • Ordinal
           • Has a value but that is not for making operations

2. Probability samples

   • The part selected is a sample of a population
     • Non-probability
       • Convenience
       • Voluntary
       • Quota
     • Probability
   • Simple random sampling methods
     • Stratified (stratos)
       • Characteristically divided groups
     • Clusters
       • Every member is assigned to a group
     • Systematic
       • Based on a following order
     • Multistage
       • More that 1 sample method

3. Measures of position

   • Deciles
     • D1, D2, D3....D10
   • Quartiles
     • Q1,Q2,Q3,Q4
   • Percentiles
     • 0-100%
   • Box plot
   • Z-score
     • X-Xa / S

4. Measures of dispersion

   • Chevychev´s theorem
     • 1-1/k^2
       • K=# of S
   • Standard deviation (S)
     • square root of X-Xa / N
   • Coefficient of variation
     • S/Xa

5. Measures of central tendency

   • Mode
     • Most repeated value
   • Median
     • Mid Value in list
   • Mean
     • All values divided between total variables

6. Visual displays of data

   • Frequency based
     • Number of times an event occurs
     • Relative frequency: f/n
     • Circle / pie
     • Bars
     • Histogram
     • Steam and leaf
     • Linear