I used Epi-Info to work to find out if there was a statistical difference between my groups (one exposed ('equipmentd') and one unexposed ('no equipment') to a factor which may increase an outcome (correct). When I gve the command tables 'equiment' 'correct' using 'Tables' in 'Analysis' to generate a 2x2 table, do a chi squared test and determine the risk ratio, the risk ratio calculated is not the incidence of outcome in the group exposed to the factor over the incidence of outcome in the unexposed group. When I copy the 2 x 2 table I generated into the Statcalc (2x2 table chi squared and risk calculator) (adapted to the appropriate order so that exposed and affected individuals are in their appropriate groups, I generate the same chi squared number, p-value and risk difference but the risk ratio is different, now equal to the incidence of affected individuals in exposed group over the incidence of affected in unexposed individuals
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