Multi-line characterization of whole molecular clouds using stratified random sampling

We have developed a new technique to characterize the multi-line emission from molecular clouds using statistical sampling. Our method uses available extinction maps select relatively small sample of cloud positions that cover full range column densities in cloud, and can be observed with only modest investment telescope time. Here we present first results applying this Perseus nearby star-forming region contains population both isolated clustered protostars. used IRAM 30m observe 100 random two orders magnitude H2 density. These been over 3mm wavelength band together selected portions 2 1mm bands. find properties most species are strongly correlated density whole they reproduced relative simple radiative transfer model.