I have seven different groups measuring fluorescence over 20 hours. I have made the graphs, and I would now like to calculate the area under the curves of the different groups. A subset of my data looks like this:
Condition Hour N Fluorescence
0 J/cm2 0 2 1537.0
0 J/cm2 1 2 2343.0
0 J/cm2 2 2 1907.0
0 J/cm2 3 2 1632.5
0 J/cm2 4 2 2864.0
0 J/cm2 5 2 3518.5
TBHP 0 2 11231.5
TBHP 1 2 11144.0
TBHP 2 2 11068.5
TBHP 3 2 10881.5
TBHP 4 2 10662.0
TBHP 5 2 10530.0
I have read a lot of different threads on the same subject, but it's always with either only one group or with different columns, and I do not know how to translate that to my data.
Right now I am using the trapz function from the zoo package:
AUC=trapz(Hour, Fluorescence)
But that only gives me the overall area, or I would have to do the groups individually, which I would prefer not to do.
I would be happy to use a different function or whatever, but my preferred outcome would be something like this:
Condition AUC
0 J/cm2 0
TBHP 1
Or set up so I could do a barplot of the different areas.
Thank you in advance!
Assuming your dataframe is called dat and the trapz()-function only requires one parameter you could try:
aggregate(dat$Fluorescence,by=list(dat$Condition),FUN=zoo::trapz)
(I haven't 100% tried out this call, but the aggregate() function might at least point you into the right direction (I hope...))