A Quiz to Test Proportional Perception of Visually Encoded Quantities
http://www.everydayanalytics.ca/2014/03/data-visualization-perception-quiz.htmlFor each question, enter a number greater than or equal to 1, expressing the size of the larger quantity as a multiple of the smaller, which may include decimals (e.g. if the larger quantity is larger by a factor of 5, enter 5.0; if you judge the larger quantity to be two-and-a-half times as large as the smaller, enter 2.5).