it was a problem set type question, with details obscured to avoid our preconceptions, then the true picture revealed afterward; thus, no way of looking up that

it was a problem set type question, with details obscured to avoid our preconceptions, then the true picture revealed afterward; thus, no way of looking up that source. In any event, the data was from WWI and the point was that using their own data they drew the wrong conclusions for their theater based on having plotted it wrong. Had they basically transposed some axes (but counterintuitively to the way they were thinking) the correct trendlines popped right out. We had another similar problem based on the shuttle Challenger o-ring failure/temperature data, given to us as racing car blown engines. The point of these exercises was to learn to focus on the data statistically/analytically and not by eyeballing presentations, and the obscuring/revealing of the truth was to drive home the point that "lives can depend on this".