How do I setup my data for mann whitney?

Hi, I have difficulties using SPSS for my study, I'm not entirely sure which analysis to make. I'm trying to compare the velocity of sneezes between groups (neuro disorder + non-neuro). e.g. I'm having 15 participants with results ranging from 0.1 to 0.6 and a control group of 15 people with results ranging from slightly faster results.

My question is how to I properly set these up? I've been trying to use the Mann-Whitney approach but I cannot seem to get any answer out of it. I think my problem is that I'm just terrible at using the program, trying to make two different variables that I'm trying to run against each other.
I often get the "not enough valid cases" - error message. What's up?

I've been trying to use Youtube for help, but there are no youtube-videos of a similar problem? So I have Group A, 15 different results, ranging from 0.1 - 0.6, and a control group ranging 0.02 - 0.3, and a different parameter (age) which I'd like to also run into the mix. How do I set this up?

I'm dumb. /JP


TS Contributor
You need 3 columns (one for each variable), and 30 rows (one for each participant).
In one column, you specify each participant's group membership. In the other column,
you indicate each participant's velocity. And in the third column, his/her age.

You can compare groups using t-test or U-test. You can include age by using
general linear model ->univariate. There, you put age into the "covariates" box and
group into the "fixed factors" box.