I'm working with some published ratio data for isotopes of uranium (238U) and lead (208Pb and 206Pb). The data are published in ratios of 238U/208Pb and 206Pb/208Pb, but I need the data to be in the form 238U/206Pb, which is simple enough to do. 238U = a, 208Pb = b and 206Pb = c:
(a/b) / (c/b) = a/c
(238U/208Pb) / (206Pb/208Pb) = 238U/206Pb
Each of the original isotope ratios has an associated error value, which is given as an absolute value at the 1 sigma level. Using the available data e.g. ratio and error values, would it be possible to calculate the associated error for the 238U/206Pb ratio, and if so, how would one go about doing this?
Here's an example of some data, I've also included a ρ (correlation coefficient for the original ratio data in case it's of any use.
206Pb/208Pb 1σ abs 238U/208Pb 1σ abs ρ 1.235 0.054 1652 119 0.9912
Many thanks, Chris