2. IDENTITY
• Identity is defined as the assignment of numbers to the values of
each variable in a data set. Consider a questionnaire that asks for a
respondent’s gender with the options Male and Female for instance.
• The values 1 and 2 can be assigned to Male and Females
respectively.
• Arithmetic operations can not be performed on these values
because they are just for identification purposes.
• This is a characteristic of a nominal scale
3. MAGNITUDE
•The magnitude is defined as the size of a measurement
scale, where numbers (the identity) have an inherent
order from least to highest.
• They are usually represented on the scale in ascending
or descending order.
•The position in a race, for example, is arranged from the
1st, 2nd, 3rd to the least.
•This example is measured on an ordinal scale because it
has both identity and magnitude.
4. EQUAL INTERVALS
•Equal Intervals are defined as the scale that has a
standardized order. I.e., the difference between each level on
the scale is the same.
•This is not the case for the ordinal scale example highlighted
above.
•Each position does not have an equal interval difference.
• In a race, the 1st position may complete the race in 20 secs,
the 2nd position in 20.8 seconds while the 3rd in 30 seconds.
•A variable that has an identity, magnitude, and equal interval
is measured on an interval scale.
5. A MINIMUM VALUE OF ZERO
•Absolute zero is defined as the feature that is
unique to a ratio scale.
•It means that there is an existence of zero on
the scale, and is defined by the absence of the
variable being measured (e.g. no qualification,
no money, does not identify as any gender,
etc.
6. MEASUREMENT AND
QUANTIFICATION
•Standard definition of measurement is the estimation of
the ratio between a magnitude of a continuous quantity
and a unit magnitude of the same kind.
• Formally expressed, a scientific measurement is:
•Where Q is the magnitude of the quantity, r is a real
number and [Q] is a unit magnitude of the same kind.
7. EXTENSIVE AND INTENSIVE QUANTITIES
• Extensive quantities are those that depend upon the amount of material.
• Examples would include the volume, or the heat capacity of a body.
• The heat capacity of a body is the amount of heat required to raise its
temperature by one degree, and might be expressed in J Co−1.
• Intensive quantities do not depend on the amount of material.
• Temperature and pressure are examples.
• Another would be the specific heat capacity of a substance, which is the
amount of heat required to raise unit mass of it through one degree, and
it might be expressed in J kg−1 Co −1.
• This is what is commonly (though loosely) called “the specific heat”,
but we shall use the correct term: specific heat capacity.
8. EXTENSIVE AND INTENSIVE QUANTITIES
ExtensiveProperty
An extensive property of a system depends on the system size or the
amount of matter in the system.
There are properties such as length, mass, volume, weight, etc.
Intensive Property
An intensive property is one that does not depend on the mass of the
substance or system.
Temperature (T), pressure (P) and density (r) are examples of intensive
properties
