The mean (or average) is a good choice for data with a normal distribution. However, if your data has extreme scores, such as the difference between an Uber and everyone else, you should look at the median or 90th percentile, because it's much more representative of your sample.
Median and 90th percentile are still pretty meaningless for the question that First Round is asking, notably "If I want to maximize my financial returns, what qualities should I look for in founders?" Miss that one company at the 99th percentile, and your return could be 10x lower.
