1. (A)  Scatter plot representing the difference between YPAQ-derived MVPA and accelerometer-derived MVPA plotted against the criterion method (accelerometer); the regression line applied indicates that residuals increase as MVPA increases.
(A)  Scatter plot representing the difference between YPAQ-derived MVPA and accelerometer-derived MVPA plotted against the criterion method (accelerometer); the regression line applied indicates that residuals increase as MVPA increases. (B) Fitted values from figure 3A versus residuals; this plot visually confirms a tendency for greater measurement error at higher levels of MVPA. MVPA, moderate-to-vigorous physical activity; YPAQ, Youth Physical Activity Questionnaire.
Paul Robert Walker McCrorie et al. BMJ Open Sport Exerc Med 2017;2:e000163
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