I am a biologist and I need some math help. I am writing a paper about how population density affects life-history traits of a snail. I want to list descriptive statistics of several life-history traits but I only need help with growth rate. We measure growth rate by measuring the shell length of each snail once a week using calipers and the way we calculate growth rate is ((Size at sexual maturity- initial size in the experiment)/ days until size at sexual maturity was reached). The reason we use "size at sexual maturity" in this equation is because the growth of this organism slows down once it reaches sexual maturity, which is at 3 millimeters.
I want to list descriptive statistics of growth rate so I need to make sure the values have a unit of measurement. However, what I have right now is median: ## (m per day up until sexual maturity at 3mm) I would have to write this measurement unit multiple times and I want to short-hand it. I was thinking of mm/d up until 3 mm but I think the "up until" part is still too many words. Do you all have any notations for "up until" or "once reach"? I was considering mm/d ≥ 3mm but I feel that measurement unit reads as millimeters per day greater than or equal to 3 millimeters and that's not what I am trying to convey.
Any suggestions?