What are the defining characteristics of the Ratio Level of Measurement?
Equal Intervals between points of that scale and a true zero.
Most measurement in the physical sciences and engineering is done on ratio scales. Mass, length, time, plane angle, energy and electric charge are examples of physical measures that are ratio scales. The scale type takes its name from the fact that measurement is the estimation of the ratio between a magnitude of a continuous quantity and a unit magnitude of the same kind (Michell, 1997, 1999). Informally, the distinguishing feature of a ratio scale is the possession of a zero value. For example, the Kelvin temperature scale has a non-arbitrary zero point of absolute zero, which is denoted 0K and is equal to -273.15 degrees Celsius. This zero point is accurately representing the particles that compose matter at this temperature having zero kinetic energy.
The ratio level of measurement is the highest level of measurement in statistics. It possesses the following defining characteristics:
1. A natural zero point: The ratio scale has a meaningful and absolute zero point. This zero point indicates that the absence of a certain quantity. For example, the weight of an object can have a meaningful and absolute zero; zero weight means the object has no weight.
2. Order and magnitude: In addition to a zero point, the ratio scale maintains the properties of the lower levels of measurement (nominal, ordinal, and interval). It exhibits both order and magnitude, meaning that data can be ranked and compared based on the numeric value.
3. Equal intervals: Unlike the ordinal level of measurement, the ratio scale ensures that the intervals between measurement values are equal and consistent. Each unit on the scale represents an equal amount of the measured attribute. For example, on a scale measuring weight in kilograms, the difference between 2 kg and 4 kg is the same as the difference between 10 kg and 12 kg.
4. Arithmetic operations: One of the key characteristics of the ratio scale is that arithmetic operations, such as addition, subtraction, multiplication, and division, can be performed on the data. This property allows for meaningful calculations such as finding the average, calculating ratios, or determining the difference between two values.
To determine whether a variable falls into the ratio level of measurement, you need to consider whether it possesses all of these four characteristics. If it has all four, it can be considered a ratio level variable. Keep in mind that the level of measurement affects the types of statistical analyses that can be applied to the data.