When using buckets on an integer field, it turns the integer fields into text fields, which nullifies the natural sort order. If I plot based on the bucket field on a bar chart, 100 to 125 shows above 50 to 100. Is there a way around this?
If you wish to change order in a category field you can go to Data> Manage fields >Options > Value order then drag little hand to change the order of appearance for different categories.
It might be worth adding a formula field that will RANK the average value per interval (50-100; 100-125 etc), that you will be able to use for sorting.