Measurement Scale

Asit

3 years ago

Types of Measurement Scale

Measurement is a process of assigning numbers/values to a physical condition, phenomenon, or status. There are four different scales of measurement. The data can be defined as being one of the four scales. The four types of scales are:

1. Nominal scale
2. Ordinal scale
3. Interval scale
4. Ratio scale

Nominal scale

Example: Name, Board, Male, Female, Blood group, etc.
A nominal scale consists of a set of categories that have different names.
Nominal is naming categories without any order. You cannot put it in descending or ascending order.
When the data for a variable consists of labels or names used to identify the characteristic of an observation, the scale of measurement is considered a nominal scale.
Sometimes nominal variables might be numerically coded. For example, Men are coded as 1 and Women as 2.
- - If we say – the temperature inside the room is comfortable – Then the temperature as a variable is nominal.
  - If we say the outside Temperature is uncomfortable – Then the temperature as a variable is nominal.

Ordinal scale

Example: Customer rating for services offered as excellent/good/poor.
Ordinal – relating to the order of something in a series.
The data obtained are the labels—excellent, good, or poor
- - Individual data has properties of nominal data. Excellent is nominal data. But when put together as excellent/good/poor, it becomes ordinal data.
  - Data can be ranked or ordered, with respect to the customer rating of service quality.
An ordinal scale consists of a set of categories that are organized in an ordered sequence. Measurements on an ordinal scale rank observations in terms of size or magnitude.
Data exhibits properties of nominal data and the order or rank of data is meaningful, the scale of measurement is considered an ordinal scale.
- - If we say – the temperature inside the room is cold outside the temperature is warm and in the desert area temperature is hot – Then the temperature as a variable is ordinal.

Other Examples:

Restaurants food rating
- - - Very good
    - Good
    - Not good
    - Poor
Performance of school students
- - - I^st
    - II^nd
    - III^rd
Evaluating the mobile signal breakdown
- - - Very often
    - Often
    - Not often
    - Not at all
Survey question
- - - Totally agree
    - Agree
    - Neutral
    - Disagree
    - Totally disagree

Interval scale

Example: Percentile, CGPA, Grade, Temperature in degrees Fahrenheit (20⁰F), Temperature in degree centigrade (70⁰C), pH value, SAT score, Specific gravity, etc.
An interval scale consists of ordered categories that are all intervals of exactly the same size. Equal differences between numbers on the scale reflect equal differences in magnitude.
A zero point on an interval scale is arbitrary and does not indicate a zero amount of the variable being measured.
- - On the Temperature Celsius scale: zero degree (0^oC) temperature is defined as the temperature of ice and water mixture in equilibrium at 1 atmosphere. Therefore 0^oC is a reference point, not an absolute zero. Hence Celsius scale is an interval scale.
  - On the Fahrenheit scale: Zero degree 0^oF temperature is considered as the freezing temperature of brine. Therefore 0^oF is a reference point, not an absolute zero. Hence Fahrenheit scale is an interval scale.
Interval scale has Ordinal data properties + fixed interval value. Example: temp 20^OC, 21^OC, 22⁰C….., the temp can be taken in an interval of 1⁰C.
The interval scale is quantitative as it can quantify the difference between the values. It allows calculating the mean and median of the variables
- - If we say – the temperature inside the room is comfortable and the outside temperature is uncomfortable – Then the temperature as a variable is nominal.
  - If we say – the temperature inside the room is cold outside the temperature is warm and in the desert area temperature is hot – Then the temperature as a variable is ordinal.
  - If we say – the temperature inside the AC room is 22°C and the temperature outside the room is 45°C – Then the temperature as a variable is Interval.

Ratio scale

Example: height, weight, age, marks, speed, distance, Temperature in Kevin, light intensity, etc.
A ratio scale is an interval scale + with an absolute zero point.
The ratio scale has an absolute zero
It doesn’t have negative numbers, because of its zero-point feature.
- - The temperature scale in Kelvin is a ratio scale variable because its zero value is absolute zero (0^ok). 0^o K is the lowest possible temperature.
Ratio is a numerical value therefore it can be added, subtracted, multiplied, or divided
- - If we say – the temperature inside the AC room is 22°C and the temperature outside the room is 45°C – Then the temperature as a variable is Interval.
  - If we say – the temperature inside the AC room is 295°K (273+ 22) and the temperature outside the room is 318°K (273+45) – Then the temperature (measured on the Kelvin scale) as a variable is Ratio.

Comparison of Nominal scale, Ordinal scale, Interval scale, and Ratio scale:

Refer comparison in the below table