How do I get a specific answer for the definition of class width? What exactly is the definition of CLASS WIDTH? Thank you!

It's basically the... how to say it... the range if you like. It's better with an example. Let's say, upon a sensus, it was found that the number of luggage within the range of 2kg and 3kg was 10. The class width is (3-2=)1kg. Anyway, that's what I'm taught, for my level.