STATISTICS

STATISTICS

1. Representing data

   • bar chart
   • Histogram
   • pie chart
   • Stem and leaf
   • line plot

2. analysing data

   • averages
     • central tendancy
       • Mode
         • most occuring value in a list
           • eg} 1, 2 ,3 , 2 , 4, 2 mode = 2
       • mean
         • sum of all values divided by number of values
       • Median
         • middle value when values arranged in ascending/descending order
           • eg} 1, 2, 3, 4, 5
   • spread
     • Variability
       • Range
         • difference between highest and lowest value
           • eg} 1, 2, 3, 4, 5 range = 5 - 1 = 4

3. types of data

   • Numerical
     • qualatitive
       • discrete
       • continuos
   • categorical
     • quantatitive
       • unordered
         • nominal
       • ordered
         • ordinal

4. collecting data

   • primrary data
     • methods of primrary data collection
       • questionnaire
       • sample survey
       • observational study
       • designed experiment
     • advantages
       • first hand
       • you know its source
       • accurate
     • disadvantages
       • time consuming
       • possibly expensive
   • secondary data
     • advantages
       • cheap
       • easily obtained
       • pre collected
     • disadvantages
       • not always accurate
       • unknown source
     • secondary data collection
       • census
       • internet
       • newspaper