Dillon DanialScientists figure out how much pot is in a jointverified_publisherFox News - By Kate Seamons"Of course I know how to roll a joint," said Martha Stewart in 2013. But if she did it properly, how much pot would she use? A new study attempts to answer that question. Reporting in the journal Drug and Alcohol Dependence, the researchers point out that the quantity hasn't thus far been …