“…The methods to deal with missing values include ignoring, discarding, filling manually, filling with attribute mean or median, filling with the same sample mean, filling with values determined by regression, and other speculative means 109 . In particular, Júnior et al introduced eight methods used to deal with missing value: ignoring, discarding, mean import, medium import, last observation carried forward (LOCF), linear interpolation, spline interpolation, and piecewise cubic Hermite interpolating polynomial (PCHIP) 110 . They analyzed the performance of these eight methods in predicting students' performance through experiments.…”