Calculating Risk - Number of Users affected

Hi there, 

For some reason I seem to be at a loss in calculating risk. 

I have a formula test field which must hold the following values: 

• No Impact
• Low
• Minor
• Major
• Critical

The conditions are as follows: 

If [Classification] = "Risk" then "No Impact". 
If [Number of Users Affected] less than 96 then "Low".
If [Number of Users Affected] greater than 96 but less than or = to 1200 then "Minor"
If [Number of Users Affected] greater than 1200 but less than 7500 then "Major"
If [Number of users Affected] Greater than 7500 then "Critical"

I've tried keeping a separate field as well to assign a case value based off of the Condition and then a separate field to give the "Impact" based off of the resulting case value. However, I seem to be struggling to pull a comparison between two different numbers, i.e If great than or equal to 96 and less than 1200 = "minor".