My book says that ratio levels of measurement is the highest form of measurement and adheres to the same rules as as interval level measurement (distances between intervals of the scale are numerically equal), but it can have an absent property.
The examples are weight, height, blood pressure, pulse, etc.
How can weight or height be a ratio measurement? What thing being measured for weight has not weight? Or has no height? I understand no blood pressure or pulse.
Thanks 🙂
Best Answer
If you have 1kg of chocolate and every day you eat 100g then after ten days you have 0g of chocolate, i.e. none left. As importantly, after five days you can meaningfully say you have half the chocolate you had initially.
Now try this with temperature measured in degrees Celsius or Fahrenheit. You cannot meaningfully say that air at $2^\circ$ is twice as hot as air at $1^\circ$, or that air at $0^\circ$ has no heat, since you can cool air well below $0^\circ$. Measure temperature in Kelvin from absolute zero and you can make similar kinds of statements (though the air may have frozen by then).