What is interval data
As it is obvious from its name, this type of the data includes intervals of real numbers e.g. age and temperature.
Depends on type of intervals and the purpose of analysis, you can whether treat intervals like ratio data, which gives you a good ability to apply different statistical methods on your underlying data, or treat them like ordinal data, which gives you the opportunity to consider your data in the form of different categories.
No matter which method you use, it is important that your intervals have the same length, especially when you want to visualize them. Otherwise it could be misleading for you and the readers of your report (usually the management team).
More about other data types