ELISA Histogram and Error Bars

[karaduman]

Hello everyone,

I have to write a lab report about ELISA (Direct and Sandwich). One of the tasks is to draw histograms from the data we obtained. Basically we have three serums and we are looking for IgG and IgE. Each sample has two wells so two data is available.
After finding the average of G1, E1, G2, E2, G3 and E3 plotting the histogram is not a problem. But the next question is asking us to draw error bars!!! I have gone through lots of articles and journals and everyone uses error bars in their ELISA data presentation but no one describes how you would do one???

Any ideas about how to place error bars into histograms? Do I have to find the Standard Deviation? Student's t Test? Percentage error bar?

Thanks
Serif