I work with a dataset that contains information on cells (%) after stimulation over a period of time. In order to asses the effect of the stimulation, I've subtracted the negative control (non-stimulated cells) from the stimulated cells. This often resulted in negative outcomes, which have been set to zero. Based on the reasoning that if there are lower/equal cells produced after stimulation compared to the negative control, there is no reaction en thus 0 stimulation going on.
Now I would like to know whether these assigned zero's are 'correct' and thus statistically different to the lower values in my data set and whether or not all counts below 1 (or another value) rather than below 0 should be set to Zero.
How can I tackle this in R?
Would the Score Tests for Zero-Inflation of Van den Broek, Jan. 1995. be appropriate?
Snapshot of the df:
-  NA NA NA NA NA NA NA 0.0000 1.1500*
-  0.0000 NA 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000*
-  0.0000 0.0000 0.0000 0.0000 0.0000 NA 10.8000 0.0000 0.7350*
-  NA 4.3550 NA NA NA NA NA 5.1950 3.4750*
Thank you for your help!