Scales of measurement Notes
Question – Discuss scales of measurement with suitable example.
Answer – Measurement is in the center of science. Measurement can be defined as the process of specifying a number for psychological or physical characteristics by following certain rules. There are four different types of measurements. They are nominal, gradual, interval and proportional. We will learn more about them because these scales are related to the use of correlations.
Scales of Measurement
3 Equal Interval Scale
1 Nominal – Nominal is the simplest type of scale. When the number is assigned to the purpose of identification, then these numbers are called as nominal numbers. The general examples are numbers written on jerseys of cricket players. They do not show that there is better or worse than each other. They simply serve the purpose of identification. No mathematical operation with these numbers is possible.
2 Ordinal – When the number assigned to an attribute is the property of the order, these numbers are called Ordinal scale. The general example is the merit list number. Ranking of batsmen or bowlers by the ICC is also a gradual scale. You will notice that there is an order property on this scale. Which means that the first is better than everyone else, the second is lower than the first but better than the others, and so on. But it does not guarantee that the distance between them is equal.
3 Equal interval scale – The equal interval scale is in which there is an additional asset of equal distances between any two consecutive units. See examples of Celsius scale of heat measurement. Answer the following two questions:
1) Does the difference between 25°C and 50°C be the difference between 75°C and 100°C?
2) Is 50°C temperature doubled to 25°C?
Most of you will get the first answer right. The answer is yes. “Difference is the difference of 25°C (that is 50°C – 25°C = 100°C – 75°C = 25°C). Now, most of you will be tempted to say yes to the second question. But this is a wrong answer. You will wonder why? The reason for this is Celsius level. The lowest possible temperature is not 0°C. The actual zero of the temperature is not 0°C, but it is very low at 273.15°C. So 25°C temperature is – 25°C from 273.15°C Therefore, 25°C will be more than double the 50°C. This is actually 323.15°C.
4 Ratio – Ratio scale has all the properties of the same interval scale. But its main advantage is that there is a real zero in it. This absolute absence of zero quantity indicates the scale on this scale. It has the property of the order, the constant distance between the units continuously, and the actual zero. This is the reason that it is the best version of the scales.