The in range validation is used to make sure the data entered falls in between a starting value and an ending value. When setting up this validation, the lowest acceptable value would go in the box on the left and the highest acceptable value would go in the box on the right. An example would be a teacher entering in student's test scores. You would want to enter in a range between zero and 100. This way, no one could accidentally type in a score of 700 when they meant to type in 70.
The in range validation setting is primarily used for fields defined as number, date or time data types. The in range option can even be used for text but any form of text range operation is very uncommon. I guess you could use the timestamp data type as well for data entry validation but I don't see that many users manually entering in timestamp related information. Timestamp data would normally be auto entered ( via a calculation ) or by a execution of a script step.
FYI ... it would not be uncommon for the range validation setting to be used in concert with one of the other validation settings. A number range validation would likely be used with the numeric only strict data type validation.