topic jmp - Process behind how jmp calculates quartiles in Discussions

jmp - Process behind how jmp calculates quartiles

NewJMPUser1 — Tue, 04 Feb 2025 23:27:53 GMT

I am new to jmp. I have been using Analyze - Distribution to get the quartiles for a quantitative variable.

But when I went to double check jmp's process, I was confused.

I typed into jmp:

9 32 48 52 57 59 60 64 65 70

jmp tells me that Q1 is 44, but finding Q1 by hand and using my TI-84 gives me 48. Also, jmp tells me Q3 is 64.25 when by hand it is 64.

Can someone tell me how jmp is calculating the quartiles behind the scenes?

Thanks!

txnelson — Wed, 05 Feb 2025 03:23:28 GMT

The JMP Online Help contains a page on the Statistical Details for Quantiles

Help=>JMP Online Help

You can also get there by using the "?" tool and click on the Quantiles report in the Distribution Platform's output

Which will bring up

where you can click on the link and it will take you to the Statistical Details for Quantiles help page

I hope this gets you what you need