How did I miss this example of the ecological fallacy when writing ‘The Shock of the Mean’!
If we collect a man’s urine during twenty-four hours and mix all this urine to analyze the average, we get an analysis of a urine which simply does not exist; for urine, when fasting, is different from urine during digestion. A startling instance of this kind was invented by a physiologist who took urine from a railroad station urinal where people of all nations passed, and who believed he could thus present an analysis of average European urine!
Claude Bernard, quoted on p 92 of The Empire of Chance
I’m overly proud of the post title.