I sympathize with what you are trying to do, but you are right when you say oversimplifications abound. I do Market/Business Intelligence for a living. I repeatably see the results of split tests change drastically after 100 results per option come in, I have even seen 1000 samples per option change. Human beings don't always fit into a nice standard deviation. A holiday, or the weather, or unknown variable X will just go ahead and mess everything up for you. Sure, if I had to make a decision based JUST on this data I would keep a baby instead of a puppy, but I wouldn't be nearly as confident as the article writer is.