I'm working with a few continuous variables, as below:
# A tibble: 6 x 3 pH `Log Chl-a` `Log Toxin` <dbl> <dbl> <dbl> 1 8.1 1.30 3.15 2 8.36 0.968 3.30 3 8.03 1.21 3.90 4 7.86 1.10 2.79 5 7.81 1.19 3.30 6 8.04 1.46 3.41
I know from literature there is relationship between pH and chl-a, and both would be related to toxic algae levels in a water body.
I want to establish a trigger using these variables. So, if chl-a and/or pH goes above a certain level, I can be sure that toxin levels in the water body are elevated.
Unfortunately, after looking at regression between pH vs toxin and chl-a vs toxin, the relationship looks relatively poor (R=0.26 and 0.29 respectively).
My question is, how could I set up a threshold/trigger of either chl-a, pH, or the combination of the two, to predict high toxic algae? Will regression help yield this trigger value?