Value input for several dependent ranges

Question

My system measures events for event sets. The activity level for each event set is based on the amount of events in that set. The numbers in the image below illustrate the amount of events needed for each level in every event set. E.g., if the amount of events for set 1 would be 7, the activity level would be Medium. Each set can have different activity level ranges.

1

A user can set the activity level ranges manually. And if user makes a change (for example, set the minimum medium in event set 2 from 8 -> 6) the other activity levels needs to be corrected also (maximum in Low needs to change from 7 -> 5).

So my question is: what kind of UI would be an easiest way for user to adjust these activity level ranges? I was thinking that a table where each value is an input field. And when a user adjusts a value, other values are corrected automatically. Example bellow:

However, I am not sure is this an easy to understand solution. Should I use slides instead of a table or perhaps just a form. Any ideas?

Thanks!

Update: The first version looked like this, only the Medium fields were editable. I feel that it might be difficult to understand that you can change other values based on the Medium range only. Not sure..

A new idea: the minimum value in Low is always 1, so would it be better if you could only change the maximum values of Low and Medium?

Answer 1

Try limiting the number of inputs, and give users indications when the bounds update.

Since the value range needs to be continuous, can you reduce the number of inputs, so users can see when they update the upper bounds on Low and Medium the corresponding lower bounds update?

This way you go from 5 inputs to 3, and the updates could even have a little animate on tab out to show the corresponding next bound enumerate. Something very subtle.

NOTE (update): in response to jakopo's answer to my question that the minimum bound is 1, you now have 2 inputs, as per his updated post.

Using sliders

Sliders tend to be tricky, and have their own set of usability problems.

Nielsen Norman Group: Slider Design: Rules of Thumb

Selecting a precise value using a slider is a difficult task requiring good motor skills, even if the slider is well designed. If picking an exact value is important to the goal of the interface, choose an alternate UI element.