Quantitative, continuous, discrete and categorical data

Categorical variable

Categorical variables contain a finite number of categories or distinct groups. Categorical data might not have a logical order. For example, categorical predictors include gender, material type, and payment method.

Quantitative variables can be classified as discrete or continuous.

Quantitative data is data expressing a certain quantity, amount or range. Usually, there are measurement units associated with the data.

Discrete variable

Discrete variables are numeric variables that have a countable number of values between any two values. A discrete variable is always numeric. For example, the number of customer complaints or the number of flaws or defects.

• Bar graph: A diagram in which the numerical values of variables are represented by the height or length of lines or rectangles of equal width

Continuous variable

Continuous variables are numeric variables that have an infinite number of values between any two values. A continuous variable can be numeric or date/time. For example, the length of a part or the date and time a payment is received, or the blood type of a person: A, B, AB or O.

• Histogram: A diagram consisting of rectangles whose area is proportional to the frequency of a variable and whose width is equal to the class interval.

BASIS FOR COMPARISON	DISCRETE DATA	CONTINUOUS DATA
Meaning	Discrete data is one that has clear spaces between values.	Continuous data is one that falls on a continuous sequence.
Nature	Countable	Measurable
Values	It can take only distinct or separate values.	It can take any value in some interval.
Graphical Representation	Bar Graph	Histogram
Tabulation is known as	Ungrouped frequency distribution.	Grouped frequency distribution.
Classification	Mutually Inclusive	Mutually Exclusive
Function graph	Shows isolated points	Shows connected points
Example	Days of the week	Market price of a product