8. Let’s say that in one city 17% percent of a class is single and in another 3% is. When we average the two classes we will get 10%, but we would be better served and we would be helping those singles more, if we looked for a reason specific to that city.
I don’t know about the rest of the letter, but the math in this paragraph is flawed. Percentages are not averaged this way, as anyone can see if they just try it out.
Let’s call the city with the 17% singles city A, and the city with 3% singles city B.
If each city had 100 students in the class, than city A would have 17 singles and city B would have 3 singles. That’s 20 singles of 200 students and yes, the average is 10 singles or 10%. But what are the odds that both cities have the same number of students in the class.
Let’s say city A has 300 and city B has 50. Now, city A’s 17% is 51 guys, and city B’s 3% is 1.5. That’s a total of 52.5 guys out of 350, which is 14.7%.
On the other hand, if city A has 50 and city B has 300 it works out to 8.5 guys in city A and 9 guys in city B, for a total of 17.5 guys out out of 350, or 5%.
If they are going to make a case, they should use accurate arithmetic (yes, it’s not even advanced mathematics).