Prince Johnny wrote:
No you don't, you just need to express the percent then use any analogy that puts in perspective for the most people..
So have the reader imagine you boss walking in and offering you a 5.7% raise immediately. Or, a 5.7% increase in the height of all women would bring the average height of women (from 64.6 to 68.3) to within 1.7 inches of the average height of men. That's a difference people would notice, and it would be proportional because it's all percentage. Suddenly 5.7% is a difference they can conceptualize.
I think we still run into some trouble here. If you quantify how much of an outlier he is, you just invite people to either suggest other outliers as evidence that he is legitimate or to find reasons why he might be an outlier.
I think it's better to base the argument in things that no-one can dispute - stick to what is normal and suggest how improbable it is that someone call fall a few standard deviations away from the mean on so many occurrences. There's so much variation in training and running a marathon that you're much better off sticking to the body of the bell curve.
What is a normal progression in race time for a marathon runner of his experience level?
What is the normal effect of his types of injuries on race times?
What was the average response to the poor Boston race day conditions that he cited?
On average, how many photos were taken per Lehigh marathon participant?
Without quantifying anything at all and averaging across a large number of confounding variables (age, weight, talent, etc), we can probably all agree that Rossi is not in the body of the bell curve for these four items. How many other measures can me make the same claim for? How likely is it to defy statistics so many times?