I was hoping someone would correct me on that. So 84-65 = 19 years, and 2/19 = 10.5% predicted population churn in two years. 14% is 3.5%/10.5%, or 33% higher than the demographic factor alone would predict.
Is there a less allegedly ambiguous term for the "traditional" definition of average, that is, the sum of many measurements of the same characteristic, divided by the number of elements measured?
Average intelligence, for example, refers to median intelligence (equivalent to an IQ of 100). Mean intelligence, however, is likely the same as median intelligence due to its normal distribution.