Data

Datum is a piece of information. A number of datum is data

Research starts with data collection. Data collection can be considered as a form of measurement.

Measurement

Measurement is the allocation of number, label or definition to a “Stuff” we want to measure. “Stuff” we want to measure is called theoretical framework. The process of connecting theoretical framework to measurement is called operationalisation. The end product of measurement is Variable.

Variable is an attribute that varies

Differentiating different types of variables is called Scaling.

flowchart LR 
 Theoretical\nframework --> Operationalisation 
 Mearsure --> Operationalisation
 Operationalisation --> Variable

Variable Scales

Types of variables
Scale Type Math Group Basic operation Statistics
Nominal Discrete

y=f(x)

f(x) is one to one substitution

 Determination of equality

Frequency

Mode

Contegency correlation
Ordinal Discrete

y=f(x)

f(x) is monotonic increasing function

 Determination of greater or less

Median

Percentile
Interval

Continuous

Discrete

y=ax+b

General linear group

 Determination of equality of interval or difference

Rank and product moment correlation

mean

standard deviation
Ratio ContinuousDiscrete

y=ax

Similarity group

 Determination of equality of ratio or difference Coefficient of Variation

Gross difference in scales

Scale Understanding Example
Nominal They are different Brown and White
Ordinal Ordered, can be grouped Rank
Interval Numbers with meaning, no definite zero Temperature in 0 C
Ratio Numbers with meaning, has definite zero Response time
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