A ratio scale is a type of measurement scale that has a true zero point, allowing for the comparison of absolute magnitudes. This means that not only can you say that one value is greater than another, but you can also say how many times greater it is. Examples of ratio scales include measurements like height, weight, and temperature in Kelvin. In a ratio scale, mathematical operations such as addition, subtraction, multiplication, and division are meaningful. For instance, if one person weighs 80 kg and another weighs 40 kg, you can say that the first person is twice as heavy as the second. This characteristic makes ratio scales particularly useful in scientific and statistical analysis.