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Table 3 Prediction equation for FFM using all subjects

From: Predicting body composition using foot-to-foot bioelectrical impedance analysis in healthy Asian individuals

Development group (n =554)  
Measured FFMDXA 50.17 ± 11.25 kg
FFM prediction equation (FFMBIA) 13.055 + 0.204 w + 0.394 h2/ ZF-F – 0.136 y + 8.125 S (Female = 0, Male = 1), (r2 = 0.92, SEE = 3.17 kg, CV = 6.3 %) (2)
Prediction FFM 50.17 ± 10.69 kg, PE = 3.20 kg, RMSE = 2.29 kg
  1. FFM, fat free mass; SE, Standard error of estimate; FFMDXA, DXA measurement of FFM; FFMBIA, BIA prediction of FFM; h2/ZF-F, height2/impedance; SEE, standard error of estimate;
  2. Root mean square error (RMSE) = \( \sqrt{{\displaystyle \sum}\frac{{\left({\mathrm{y}}_{\mathrm{i}}^{\hbox{'}}-{\mathrm{y}}_{\mathrm{i}}\right)}^2}{\mathrm{n}}-\mathrm{p}-1} \)
  3. Pure errors (PE) = \( \sqrt{{\displaystyle \sum}\frac{{\left({\mathrm{y}}_{\mathrm{i}}^{\hbox{'}}-{\mathrm{y}}_{\mathrm{i}}\right)}^2}{\mathrm{n}}} \); where y’ is the predicted FFM, y is the observed, n is the number of subjects and p is the number of predictor variables