Select Analyze > Fit Model. Enter your response as Y and your predictor with Add (Effects) and click Run. Click the red triangle at the top left and select Estimates > Multiple Comparisons, select Comparisons with Control - Dunnett, and then click OK. Select your control level and click OK. You will get a table like this:
![Capture.JPG Capture.JPG](https://community.jmp.com/t5/image/serverpage/image-id/19250i7AE4D48F432E6601/image-size/large?v=v2&px=999)
Can you use the differences here for your purpose? Note that you can right-click on the table and select Make Into Data Table. You can now use column formulas to compute values or visualize the table with Graph Builder.
I don't know how to calculate percentages.