Types
of Measurement Scale
There are 4 Measurement Scales: Nominal, Ordinal,
Interval and Ratio scale with Nominal and ordinal having least mathematical
properties and they are qualitative (Categorical) type data whereas Interval &
Ratio having most mathematical properties and they are quantitative (Numerical)
type data.
Nominal Scale:
Nominal Scale is
the lowest measurement level. It is assigned to items that is divided into categories
without having any order or structure.
Example:
classification of section of any class, players, communities etc. Suppose We
have 5 sections may divide in section A- E. The alphabet gives us the identity
of the section assigned. The only mathematical operation we can perform with
nominal data is to count. Another example from research activities is a YES/NO
scale, which is nominal. It has no order and there is no distance between YES
and NO.
Calculation of Chi
square, mode frequency distribution is the best measure.
Characteristics of Nominal Scale
Ø A nominal scale
variable is classified into two or more categories. In this measurement
mechanism, the answer should fall into either of the classes.
Ø It is qualitative.
The numbers are used here to identify the objects.
Ordinal Scale:
Ordinal Scale is
the 2nd measurement scale. Ordinal Scale is ranking of responses,
for instance Ranking Cyclist at the end of the race at the position I, II and III.
Not these are rank and the time distance between I and II may well not be the
same as between II and III, so the distance between points is not the same but
there is an order present, when responses have an order but the distance
between the response is not necessarily same, the items are regarded or put
into the Ordinal Scale. Therefore, an ordinal scale lets the researcher
interpret gross order and not the relative positional distances.
Calculation of
Median, Percentile , Rank difference correlation is the best measure.
Characteristics of the Ordinal Scale.
- The
ordinal scale shows the relative ranking of the variables
- It identifies
and describes the magnitude of a variable
- Along
with the information provided by the nominal scale, ordinal scales give
the rankings of those variables
Interval Scale:
The interval scale
is the 2nd largest level of measurement scale A normal survey rating
scale is an interval scale for instance when asked to rate satisfaction with a
training on a 3 point scales, 5 point scales, 7-point scales, etc
Example: 5 Points scale like Strongly Agree, Agree,
Neutral, Disagree and Strongly Disagree, an interval scale is being used. It is
an interval scale because it is assumed to have equal distance between each of
the scale elements i.e. the Magnitude between Strongly Agree and Agree is
assumed to be the same as Agree and Strongly Agree. This means that we can
interpret differences in the distance along the scale. We contrast this to an
ordinal scale where we can only talk about differences in order, not
differences in the degree of order i-e the distance between responses.
The equal distance
between scale points helps in knowing how many units greater than, or less
than, one case is from another. The meaning of the distance between 25 and 35
is the same as the distance between 65 and 75.
Calculation of
Mean, Median, S.D, Product moment correlation, ANOVA & ANCOVA is the best measure
Characteristics of Interval Scale:
Ø The interval scale
is quantitative as it can quantify the difference between the values
Ø It allows
calculating the mean and median of the variables
Ø The interval scale
is the preferred scale in Statistics as it helps to assign any numerical values
to arbitrary assessment such as feelings, calendar types, etc.
Ratio Scale:
A Ratio Scale is at
the top level of Measurement which is quantitative . It allows researchers to
compare the differences or intervals. The ratio scale has a unique feature. It
possesses the character of the origin or zero points. Having zero length or
zero money means that there is no length and no money but zero temperature is
not an absolute zero, as it certainly has its effect. Ratio scales of
measurement have all of the properties of the abstract number system.
Characteristics of Ratio Scale:
- Ratio
scale has a feature of absolute zero
- It
doesn’t have negative numbers, because of its zero-point feature
- It
affords unique opportunities for statistical analysis. The variables can
be orderly added, subtracted, multiplied, divided. Mean, median, and mode
can be calculated using the ratio scale.
- Ratio
scale has unique and useful properties. One such feature is that it allows
unit conversions like kilogram – calories, gram – calories, etc.
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