topic Re: How can i choose the same observation to calculate a ratio for a series of observations? in Discussions

How can i choose the same observation to calculate a ratio for a series of observations?

PercentileBird2 — Tue, 04 Mar 2025 07:41:07 GMT

Hello, I am pretty new to jmp, but I have a question regarding creating a function column. So I have a dateset where I have recorded physiological data for the same 6 heart rate values in 16 mice. I want to choose two of these physiological variables to calculate a ratio - and I want the numerator to be the phys. value for the corresponding highest heart rate, and the denominator for another phys. value but for the middle (3rd lowest) heart rate. How can I specify this for all my 16 mice?

Re: How can i choose the same observation to calculate a ratio for a series of observations?

jthi — Tue, 04 Mar 2025 16:08:02 GMT

Can you provide example data?

Re: How can i choose the same observation to calculate a ratio for a series of observations?

PercentileBird2 — Wed, 05 Mar 2025 12:00:20 GMT

Hi, Jarmo!

Below is some example data for 4 of my animals, the E column will be my numerator and the early e' should be the denominator. So I want to calculate a ratio where E is from HR = 600, and early e' is from 400 for each animal (the HR intervals is the same for each animal)

Re: How can i choose the same observation to calculate a ratio for a series of observations?

jthi — Wed, 05 Mar 2025 13:05:28 GMT

Are other HR values important? Do you wish to keep the data format same? Just asking because the calculation is much easier to perform from table like this

You can also try to use formulas like these

numerator:

:E[Col Min(If(:HR == 600, Row(), .), :Animal ID)]

denominator:

:"early e'"n[Col Min(If(:HR == 400, Row(), .), :Animal ID)]

Re: How can i choose the same observation to calculate a ratio for a series of observations?

txnelson — Wed, 05 Mar 2025 13:37:05 GMT

Here is the formula I came up with

Col Mean( If( :HR == 600, :E, . ), :Animal ID ) / Col Mean(
	If( :HR == 400, :early e', . ),
	:Animal ID
)