The whole basis seems to be picking a range of values for the variables in the Drake equation rather than a single value for each variable. As a result, the var

The whole basis seems to be picking a range of values for the variables in the Drake equation rather than a single value for each variable. As a result, the variance multiplies significantly meaning that they find a 30% chance we're alone in the galaxy as the lower end of the deviation (and the higher end being the common notion that there should be abundant intelligent life everywhere we look). I hope they didn't spend too long making this "study" of tossing conservative estimates into a theoretical equation.