About That Global Warming Hiatus... #Fauxpause
If I want to measure how much business a shopping mall gets, I can stand by an entrance way and count the number of people who go into the mall. If I stop every tenth person on the way out and frisk them for their receipts, I can estimate the per-person amount of money spent, and multiply that by ten to get an idea of how much business is represented by the particular entrance way I am sampling. This would work.