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Difference between ratio and interval scales?

Difference between ratio and interval scales?


Can you give me an example?

1 Answer

365 Team

Hey Avinash!
I’ll try to use the same example but in a different way. You tell me if that works for you.
Most things that we observe in the world are ratio variables. They are called ratios because they can represent ratios of things.
For instance, I have 2 apples and you have 6 apples. You have 3 times as many as I do. How did I find that? Well, the ratio of 6 and 2 is 3 (6/2 = 3)
Another example of a ratio variable is weight. My current computer weighs 2 kg, while my previous computer weighted almost 4 kg. I can safely say that my current computer is two times lighter (4/2 = 2).
Intervals are not as common. Temperature is the most common example. Why?
Say today is 5 degrees Celcius (41 degrees Fahrenheit) and yesterday was 10 degrees Celcius (50 degrees Fahrenheit). In terms of Celcius is seems that it is twice colder, but in terms of Fahrenheit… not really. 
But what does twice colder even mean??? Temperature is a very relative measure as we artificially created Celcius and Fahrenheit as scales. Most interval variables are such. 
Here’s a bit technical explanation from a student (Jeff Nyman) that was submitted some time ago:
‘Let’s consider the weight quiz question. Why is it a ratio variable?
Considering weight, this is defined as W = m * g. Here the idea is that W is weight of the object, m is mass of the object and g is gravity present at that region. If gravity were to be entirely zero, then the weight of the object would be given by W = m * 0. Thus W = 0. Thus weight can be zero.
In reality, as far as we know, nothing is ever entirely insulated from gravity. So the weight of an object can never actually get to 0 … but there is a definition of a true zero. It would be that place where gravity is entirely absent as a force.
And that’s a way to understand “true zero.”
If something isn’t a “true zero”, it means the zero isn’t meaningful because it doesn’t mean a true absence of something.
Considering the temperature example from the video, zero degrees Fahrenheit (or Celsius) does not represent the complete absence of temperature, which physically would mean the absence of any molecular kinetic energy. Zero Kelvin (and note we don’t say “zero degrees Kelvin”) does represent the complete absence of such molecular kinetic energy.’
Hope this helps!
The 365 Team

In addition we can say “ratio scale have zero as there natural origin”. Measure of central tendency for such variable is geometric mean.

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