Age is considered a ratio variable because it has a true zero point (birth), allowing for meaningful comparisons and calculations. Unlike interval variables, which lack a true zero, ratios can be formed (e.g., someone who is 40 years old is twice as old as someone who is 20). Additionally, age can be measured in consistent units (years), making it a clear example of a ratio scale.
Ordinal. Though more likely interval or even ratio scale.
interval
ratio
interval
Ratio
It is a ratio scale of measurement.
The year is interval scale (no natural zero); your age is ratio.
Age is none of the items listed. Age is ratio data.
Ordinal. Though more likely interval or even ratio scale.
It is ratio.
interval
interval
ratio
The ratio of a minor second interval in music is 16:15.
interval
Nominal Scale < Ordinal< Interval < Ratio
Year of birth is interval level of measurement; age is ratio.