I`m now analyzing correlation coefficient (Pearson) for mRNA level and fat content.
My problem is I`m not sure how to compute the mRNA levels (measured by Real-time PCR) in the Pearson formula and the scatter plot using Excel.
I was thinking to use the ∆Ct (target gene - reference gene), but then I found some papers using the 2-ΔΔCt, and one of them also used 2-ΔCt.
Also, I`ve been searching about how to make the scatter plot and trendline for this Pearson test in Excel.
Using Excel, I always end up with the graph for regression analysis and I don`t know how to make the graph or trendline into Pearson.
I checked the R values for regression and Pearson and they both are quite the same, although I`m kind of sure that the graph would be somehow different between those two tests.
Hope my questions aren`t (gramatically) confusing and anyone can help me because my head is spinning right now
1 reply to this topic
Posted 27 January 2009 - 03:11 AM
The standard approach is to normalize your data, generally by using the control. Although I'm unfamiliar with the 2-dCt, I do understand how dCt is trying to normalize all data for mRNAs. Also, if your qPCR contains only relatively few samples, it may be good to try to calculate a p-value. As for the correlation coefficient, there is a simple function in excel (CORREL i think) which will calculate the Pearson coefficient for you.