I've collected fluorescence data from some bacterial cells.
Each cell has a gene in it which can be induced to fluoresce. However, even without being induced, the gene will still fluoresce a little.
I have subjected the cells to a series of concentrations of inducer, including 0% inducer, and measured the resultant fluorescence over time.
The fluorescence produced from cells that have not been induced is, effectively, 'background' fluorescence. Therefore, I would like to subtract the background fluorescence from the fluorescence measured in cells that have been induced in order to determine the fluorescence that is caused by induction.
$n = 3$ for all measurements.
My question is, can I take the mean fluorescence of the uninduced cells and assume that it is the true mean? I.e. assume that its $SE = 0$. If I can do that, when I subsequently subtract the mean background fluorescence from the mean induced fluorescence, the final calculated $SE$ will be lower.
Here's some example data:
Inducer: 0% 5% 1 3411 4965 2 3427 4784 3 3412 5379 Mean 3416.666667 5042.666667 SD 7.318166133 249.0385958
Given that the background will change for each experiment, I assume that the mean background measured is the true mean for that experiment. Is that not correct?
I must state that my maths/stats skills are rudimentary at best so please bear that in mind when answering.