Experiment design - (Apr/10/2012 )

I have two questions:

1) Do standard curve need error bars? Let say for BSA standard curve, for each concentration I did 3 replicate, I find the mean and SD and plot the linear graph with error bars.

2) For Lowry assay, or other protein assays, do I need to do interday and intraday experiment? For example, in each experiment I run five replicates and I find the mean of the sample. I conduct 3 independent experiment (each with five replicate). At the end of the day I will have 3 mean values from 3 independent experiments. The final value that I will report is the mean from the means of the 3 independent experiment.

I know this is the right way of experimental design, but never read the details of experimental design for simple assay like Lowry assay. Please let me know if I do not need to follow this way for Lowry assay.

Thank you

to 1) yes, with error bars but as SEM, not as SD

Inmost sun on Sat Apr 21 14:27:10 2012 said:

Could you please explain why you use SEM not SD for error bars?

2) Yes, you can perform triplicate of BSA each independent experiments as a standard tube and calculate your samples based on the average of these tubes.