An industrial hygienist creates a standard atmosphere by injecting 250 ul of chlorine into a sealed container that is 1ft x 2 ft x 2 ft. The hygienist then measure the air by three different analytical methods, colormetric tube, sobent tube and direct reading instrument. If the results for each of the instrument was as follows: colormetric tube 2.6 ppm, sobent tube 2.0 ppm, direct reading instrument 1.9 ppm, What is the percent error for each of the methods?