This printable handbook explains eight common mistakes people make when collecting and interpreting data. Each section gives a clear definition with examples. Recognizing and avoiding these mistakes helps us critically evaluate the information we encounter. Selection BiasRegression to the MeanCorrelation and CausationClustering IllusionGambler's FallacyBase Rate FallacySurvivorship BiasSimpson's ParadoxRecommended for teens and adults. An online version is available on Critikid.