Order Within Grouping Variable

Question

I apologize if this has been answered, but I can’t find quite the right answer in the discussions.  I have a grouping variable and I performed a t test with two values in the grouping variable.  The variable values are “Before” (n=6,437) and “After” (n=264).  JMP is showing me the t-test as (Before minus After), which results in a negative value.  I understand that I can just multiply by -1 to reverse the order of how the means are being subtracted from each other, but it gets confusing to explain.  How do I make the results be (After minus Before)?  I tried sorting the data, but that didn’t work.  These are not paired observations, so I don’t need a third column with the differences.  I tried looking at the column formula, but that’s for something else.  I come from SAS and what can be done there is use formatting to alter the order of things, but I don’t see anything that looks like that in JMP.  I would appreciate any guidance.

Victor_G · Accepted Answer

Hi @LawOfAardvark73,

Welcome in the Community !
The ordering of the level is by default done in alphanumeric order, which is why JMP gives you the calculated difference as Before minus After. To specify the ordering of the level, you can add the column property Value Order to specify that level "Before" comes before level "After".

Adding this column property should give you the test result directly in the right expected order.

Hope this answer will help you,