STATISTICS

STATISTICS

1. BASIC CONCEPTS

   • Population: totality of elements or things under consideration
   • Sample: portion of the population selected for analysis.
   • Parameter: measure of overview calculated to describe a characteristic of a population.
   • Statisitc: measure of overview calculated to describe a characteristic of a sigle sample of the population.
   • Random Variables: questions dealing with a diversity of phenomena or characteristics.
     • Qualitative
     • Quantitative
       • Discrete data
       • Continuous data

2. MEASUREMENT SCALES

3. SAMPLING METHODS

4. VISUAL DISPLAY OF DATA

   • Line graphs
   • Circle graphs
   • Bar graphs
   • Stem and leafs
   • Histogram
   • Frecuency Distribution
     • Frecuency: number of times an item repeated.
     • Relative frecuency: percentage of the data represented /f/n)

5. MEASURES OF CENTRAL TENDENCY

   • Median: the value in the half of a group
   • Mean: found by adding all items and then dividing the sum by the number of items.
   • Weighted Mean:the sum of all products of items times weighting factors divides by the sum of all weighting factors

6. MEASURES OF DISPERSION

   • Range: greatest value - lowest value in the set
   • Standard Deviation
   • Chevyshev's teorem: 1-1/k^2 (k= #of s)
   • Coefficient of variation: s/x

7. MEASURES OF POSITION

   • Z-score (standard score): z=x-X/s
   • Decile: (D1, D2, D3... D10)
   • Quartile: (Q1, Q2=median, Q3, Q4)
   • Percentile: (1% to 100%)
   • Box Plot

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