Thank you Pmeems, I got it.
The next problem is, how to let the user assign the cutting point manually (how many category they need and input the value for each category manually)
For example:
Number of categories: 5
Cat 1: 10 - 20
Cat 2: 20-40
Cat 3: 40-60
Cat 4: 60-80
Cat 5: 80-100
The next problem is, how to let the user assign the cutting point manually (how many category they need and input the value for each category manually)
For example:
Number of categories: 5
Cat 1: 10 - 20
Cat 2: 20-40
Cat 3: 40-60
Cat 4: 60-80
Cat 5: 80-100