mRNA half life calculation - semi log graph - linear or exp regression??????? HELP!!! (Feb/15/2007 )

Hi There

Trying to calculate my mRNA decay half life after actinomycin D chase experiments.

My data is normalised, as % remaining after time:
1. Should i plot it on a semi log graph (ie. log y axis only) and then perform an exponential regression?
2. Should i plot it on a semi log graph (ie. log y axis only) and then perform a linear regression?
3. Should i log the data values (and if so, normal log or ln?) and then plot on a semi log graph and then use linear regression?
4. Should i log the data values (and if so, normal log or ln?) and then plot on a semi log graph and then use exponential regression?

I mucked about with excel trying various combos and I get such different results...


PLease help my mathematically impaired brain manage data!!!!!!!

how about plotting it linear. plot the real values vs time.

Hi, I am absolutely no expert in this field, but for allmost all kinetics ist makes sense to use non-linear regression, as the biological processes are not likely to be completely linear. But maybe this is different for RNA decay?