Question

a. Celsius and Fahrenheit scales have zero values. Why are they not ratio scales?

b. Provide an example of an interval scale not mentioned in the text that is not a ratio scale. If you scale has a zero element, briefly explain why the zero element does not make it a ratio scale.

c. Provide an example of a ratio scale not mentioned in the text. Briefly explain why the zero element of your scale makes it a ratio scale.

Answer 1

1. A ratio variable, has all the properties of an interval variable, but also has a clear definition of 0.0. When the variable equals 0.0, there is none of that variable. Variables like height, weight, enzyme activity are ratio variables. Temperature, expressed in F or C, is not a ratio variable. A temperature of 0.0 on either of those scales does not mean 'no heat. However, temperature in Kelvin is a ratio variable, as 0.0 Kelvin really does mean 'no heat'.

When working with ratio variables, but not interval variables, you can look at the ratio of two measurements. A weight of 4 grams is twice a weight of 2 grams, because weight is a ratio variable. A temperature of 100 degrees C is not twice as hot as 50 degrees C, because temperature C is not a ratio variable

2. Interval scales do not have a “true zero” point, so statements about the ratio of attributes in an interval scale cannot be made. Examples of interval scales include temperature scales, standardized tests,

In reality, the label "zero" is applied to its temperature for quite accidental reasons connected to the history of temperature measurement. Since an interval scale has no true zero point, it does not make sense to compute ratios of temperatures.

3. A ratio scale is the most informative scale as it tends to tell about the order and number of the object between the values of the scale. The most common examples of ratio scale are height, money, age, weight etc.

A ratio scale has a point zero characteristic, where the value of the variable has no value at all. Weight, height etc can be calculated on ratio scale because they have a real zero value. However, the temperature cannot be measured on this scale because zero degree celsius doesn’t mean there is no cold or heat for that matter. But most of the scientific variables can be measured on a ratio scale.