Which of the following variables cannot be expressed in quantitative terms?

Professional attitude cannot be directly expressed in quantitative terms, being a qualitative disposition.

It reflects an orientation or feeling that resists a natural numerical measure.

Socio-economic status can be quantified through an index of income, education and occupation.

Numerical aptitude is measured as a test score and is clearly quantitative.

Height is a physical magnitude measured on a ratio scale.

Attitudes are usually approximated indirectly through rating scales rather than direct measurement.