18 mg/kg dose 20 mg/kg dose effect of dose effect of calculator use   calculator used no calculator calculator used no calculator calculator used no calculator 18 mg/kg dose 20 mg/kg dose Significant error >10% 2/300 28/300 3/300 1/300 NS * * NS Speed of calculation in  seconds (range) 8 (2-36) 18 (2-77) 6 (1-39) 4 (1-44) ** ** ** NS * p< 0.001 Fischer exact test ** p< 0.001 Wilcoxson sign ranked test

Table 1: Comparison of occurrence of number of significant errors in drug calculation of > 10% of the dose when asked to prescribe 18 mg/kg dose and 20 mg/kg dose with and without the use of the calculator (top row). Speed of calculation (seconds) expressed as median and range for making the calculations when asked to prescribe 18 mg/kg dose and 20 mg/kg dose with and without the use of a calculator (bottom row).