Observations and Variables

• Ordinal Level - Describes ranking or order. The difference or ratio between two rankings may not always be the same.

  Examples:

  Grade Level (Grade 1, Grade 2)

  Birth Order (First Born, Middle Child)
• Nominal Level - Observations can be named without particular order or ranking imposed on the data. Words, letters, and even numbers are used to classify the data.

  Examples:

  Blood Type (A+, A-, B+)

  Student Number (20192356, 20190018)
• Interval Level - Indicates an actual amount (numerical). The order and the difference between the variables can be known. Its limitation is it has no “true zero”.

  Examples:

  IQ score (140 IQ points, 155 IQ points)

  Temperature in degree Celsius (45°C, -5°C)
• Ratio Level - It has the same properties as the interval level. The order and difference can be described. Additionally, it has a true zero and the ratio between two points has a meaning.

  Example:

  Number of Students (0 students, 23 students)

  Weight (2 kg, 7lbs)