Is there are reason why you couldn't just check if each row is greater than 25% of the highest value immediately?
You can check for maximum value in column by using Col Max()
If(:Column 2 >= Col Max(:Column 2) * 0.25,
"TRUE",
"FALSE"
)
You can of course sort the data if you need to by right clicking on the column header and selecting Sort Ascending/Descending
One way to access row and column is to use Data table subscripting , you can also use column reference and then row number like :Column 2[1]
Also a good read JMP is Not a Spreadsheet
-Jarmo