Basic Statistics : Types of Variables

Types of Variables

Qualitative data are often termed categorical data. Data that can be added into categories according to their characteristics.

Nominal Variable (Unordered list)
A variable that has two or more categories, without any implied ordering.

Examples : 
  • Gender - Male, Female
  • Marital Status - Unmarried, Married, Divorcee
  • State - New Delhi, Haryana, Illinois, Michigan

Ordinal Variable (Ordered list)
A variable that has two or more categories, with clear ordering.

Examples : 
  • Scale - Strongly Disagree, Disagree, Neutral, Agree, Strongly Agree
  • Rating - Very low, Low, Medium, Great, Very great

An interval variable is similar to an ordinal variable, except that the intervals between the values of the interval variable are equally spaced. In other words, it has order and equal intervals.

Examples : 
  • Temperature in Celsius - Temperature of 30°C is higher than 20°C, and temperature of 20°C is higher than 10°C. The size of these intervals  is the same.
  • Annual Income in Dollars - Three people who make $5,000, $10,000 and $15,000. The second person makes $5,000 more than the first person and $5,000 less than the third person, and the size of these intervals  is the same.

It is interval data with a natural zero point. When the variable equals 0.0, there is none of that variable.

Examples : 
  • Height
  • Weight
  • Temperature in Kelvin - It is a ratio variable, as 0.0 Kelvin really does mean 'no temperature.

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Deepanshu Bhalla

Deepanshu founded ListenData with a simple objective - Make analytics easy to understand and follow. He has over 10 years of experience in data science. During his tenure, he worked with global clients in various domains like Banking, Insurance, Private Equity, Telecom and HR.

16 Responses to "Basic Statistics : Types of Variables"
  1. so written in an understandable form

  2. A very good start for the beginners to continue their journey till they become master

  3. very well crafted for beginners to become master it.

  4. Really great approach to learn statistics in easy way and understandable format

  5. So a ratio is a subtype of interval data : may you correct the tree chart ?

  6. Good Explanation & easy to understand

  7. Thank u for good understandable points


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