Measurement scales

Data are measured using quantitative and qualitative scales

Knowing what scale your data use helps you to manipulate and analyse your data effectively 

flowchart LR
%%| Comment
  %% Title[Measurement scales] --> 
  Gp[Group] --> Scale[Measurement scale] --- Prop[Properties] -.- Ex[Examples]
  style Prop fill:#fff2cc,stroke:#f1c232
  style Ex fill:#d9ead3,stroke:#6aa84f
  Qual["<b>Categorical / Qualitative</b>
    Classes or groups"]
  Qual --> Nom["<b>Nominal</b> scale
    Order of categories is meaningless
    Often given names"]
  Nom --- NomProp["Mutually exclusive
    Unordered"]
  NomProp -.- NomEx["Landcover class: Wetland, Forest
    Country: Gabon, Ecuador"]
  Qual --> Ord["<b>Ordinal</b> scale
    Also knowns as Ranked
    Order has meaning, e.g. small to large"]
  Ord --- OrdProp["Ordered"]
  OrdProp -.- OrdEx["Vegetation cover: Sparse, Medium, Dense
    Staff experience: Volunteer, Junior, Expert"]
  Quant("<b>Numerical / Quantitative</b>
    Measure numerically
    Discrete or continuous")
  Quant --> Int("<b>Interval</b> scale
    Numbers with an arbitrary zero
    Adding and subtracting is meaningful")
  Int --- IntProp["Ordered
    Constant scale"]
  IntProp -.- IntEx("Date: 04-Sep-2024
    degrees Celsius: 28&deg;C")
  Quant --> Ratio("<b>Ratio</b> scale
    Numbers with a natural zero
    Multiplying or dividing is meaningful")
  Ratio --- RatioProp["Ordered
    Constant scale
    Natural zero"]
  RatioProp -.- RatioEx("Distance from protected area
    degrees Kelvin: -273&deg;K")
  Quant --> Circ("<b>Cyclic</b> scale
    Maximum is next to minimum")
  Circ --- CircProp["Ordered
  Maximum = Minimum"]
  CircProp -.- CircEx("Time: 23:59, 00:00
    Longitude: 180&deg;, -180&deg;")
  style NomProp fill:#fff2cc,stroke:#f1c232
  style IntProp fill:#fff2cc,stroke:#f1c232
  style OrdProp fill:#fff2cc,stroke:#f1c232
  style RatioProp fill:#fff2cc,stroke:#f1c232
  style CircProp fill:#fff2cc,stroke:#f1c232
  style NomEx fill:#d9ead3,stroke:#6aa84f
  style IntEx fill:#d9ead3,stroke:#6aa84f
  style OrdEx fill:#d9ead3,stroke:#6aa84f
  style RatioEx fill:#d9ead3,stroke:#6aa84f
  style CircEx fill:#d9ead3,stroke:#6aa84f

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