Continuous (Interval or Ratio) Scale Data
- Data points where there is a sense of order and rank. In addition, the magnitude of difference between each number is the same and measurable.
- Made up of two types of scales of data, interval scale and ratio scale.
- The only difference between interval and ration scale data is whether or not the scale being referred to has an absolute zero.
- Interval scale data:
- When numbers have units that are of equal magnitude as well as rank order on a scale without an absolute zero
- Scales of this type can have an arbitrarily assigned "zero", but it will not correspond to an absence of the measured variable. For example, temperature in Fahrenheit scale.
- Ratio scale data:
- When numbers
have units that are of equal magnitude as well as rank order on a scale with an absolute zero
- Examples include: heart rate, blood pressure, distance.
- For interval and ratio data can be converted into ordinal data, but ordinal data cannot be converted into continuous data.
- Can be described as a mean or median.
- Gaddis ML et al. Introduction to biostatistics: part 1, basic concepts. Ann Emerg Med 1990;19:86-89.