Ken,
I don't have excel either. You mentioned excel and left out the details:
1) you want to use Numbers
2) you don't have excel
3) you tried once an a friends computer
Providing a good problem statment and details is important. Usually we try things before reponding to see if we can figure out what you are asking then we ask questions.
What I want to see is what the actual data looks like before being distorted by conversion to dates. If you do not want to pursue no problem. I am just trying to point out that you and I have spent several exchanges without getting anywhere because of imcomplete information. Not trying to beat you up or point fingers just trying to help you understand how details matter and can speed up or slow down this process.
Your problem is tractable but I still don't kow what the data looks like. I can guess since you are entering Blood Pressure and Heart rate. But I cannot get the results with date formatting to match what you are posting.
Post back if you want to understand the problem asn we can continue.
Regards,
Wayne