Categorical & Cont variables

Categorical & Cont variables

1. Nominal

   • simplest and lowest level of measurement
   • involves classifying observations into mutually exclusive categories
   • Binary scales
     • allocation of that individual to one of only two possible categories
       • Male/Female
       • smoker/non
   • thus participants are assigned to a named category such as 'male' or 'female'
     • No particular order
       • i.e Budhist, Monks....
   • NAMES ONLY

2. Ordinal

   • ORDERED
     • involves ranking of phenomena
       • permits the numeric ranking of objects on the basis of their standing relative to each other on a specified characteristic.
         • organised along 'greater than and less than' dimensions
           • only shows relative magnitude, not quantity
           • discrete and conceptualised as having inherent order
       • Mutually exclusive
         • 1 = is completely dependant 2 = is needing another person's assistance 3 = is needing mechanical assistance 4 = is completely independent.
         • Only ranks doesn't tell whihc one is better

3. Ratio

   • represent the highest level of measurement
     • Absolute zero point
       • describe ratio properties between values as there is a true zero;
   • have all of the characteristics of nominal, ordinal and interval measures

4. Interval

   • characteristics of both nominal and ordinal data but also has the characteristics of equal spacing between categories
   • indicates how much the categories differ;
     • demonstrates equal amounts of change in a variable between equivalent distances or intervals between points on a scale
       • does not measure absolute magnitude since the zero on interval scales is arbitrary
         • the arbitrary zero does not mean there is 'nothing' of the variable being measured; for example, an IQ of zero does not mean zero intelligence – it just means someone scored zero on an IQ test – maybe because they couldn't read
   • No true 0 makes it diff to compare ratios
   • specify both the rank order of a characteristics and the distance between those objects.
     • someone whose IQ increased from 100 to 110 has had the same IQ increase as someone
       • whose IQ has gone from 110 to 120 (i.e. a 10-point increase in both cases).