Calculating Average Weight Gain Per Week

[erin1684]

Hello,
I'm new to the forum, so please let me know if I'm not describing my situation correctly.
I need to calculate the average weight gained per week for multiple patients at the hospital where I work. (this would work with weight loss as well...I'm just in the opposite business)

Currently, I collect weights every day and enter them into a spreadsheet (dates are the column headings, patient names are the row headings). I need to prepare a report quarterly that describes how many patients met their weight gain goal (2-4 pounds per week)...i.e. I need to get the average weight per week and then use those averages to calculate the change in weight per week. I am looking for a way to auto-calculate these numbers if at all possible as I have a lot of patients to analyze per quarter (p.s. I'm definitely an Excel novice, but I can teach myself pretty quickly). Another caveat: the start dates for each week are not on the same day for each patient, as new patients admit on different days over time (i.e. patient 1's admit weight is 100 on 7/1 in the example below, but patient 2's admit weight is 120 on 7/3).

This is how my spreadsheet is set up*:
Date: 7/1 7/2 7/3 7/4 7/5 7/6 7/7 7/8 7/9 7/10
Patient 1:100 99.5 100.2 101 101.5 100.4 101.2 101.5 102 101.9 etc...
Patient 2: 120 121 121.3 etc....
* Looks like when I post this, the dates do not match up with the weights...100 should go under 7/1, 95 under 7/2, 100.2 then 120 under 7/3 etc...)

Any idea how I can do this?
Thank you in advance for your time! I really appreciate it!