Categorical and quantitative variables

A variable can be classified as one of two types:

Type

Description

Minitab Data Type

Examples

Categorical

Values can be placed into a countable number of categories or distinct groups.

Categorical data may or may not have some logical order.

 

(Also referred to as qualitative or attribute)

Numeric

·    Gender (0=Male, 1=Female)

·    Survey results (1=Disagree, 2=Neutral, 3=Agree

Text

·    Payment method (Cash or Credit)

·    Machine settings (Low, Medium, High)

·    Product types (Wood, Plastic, Metal)

Date/time

·    Days of the week (Monday, Tuesday, Wednesday)

·    Months of the year (January, February, March)

Quantitative

Values can be ordered and measured.

(Also referred to as variable)

Numeric

·    Number of customer complaints

·    Proportion of customers eligible for a rebate

·    Fill weight of a cereal box

Date/time

·    Date and time payment is received

·    Date and time of technical support incident

Often, you will collect both types of data when exploring a single subject, as categorical variables are often used to group or subset the data in graphs or analyses.

Subject

Possible categorical variables

Possible quantitative variables

Household appliance sales

Type of appliance; Make and model

 

Sale price

Automobile body painting

Paint flaws (peel, scratch, smudge, other); Paint colors

Temperature of metal to be painted; Thickness of paint layer