why is it necessary for smoothed lines to never cross which smoothing function should only touch between data points smooth function how to smooth stacked lines do smooth lines cross can smoothed lines cross what is a smooth function for graphs can stacked data points be smoothed how to smooth lines on excel what is smoothing do smooth lines cross when stacked how do smoothed lines work which function allows smoothed lines to be displayed without crossing which function smoothes lines what is smoothing in excel what is the function to do a smooth line what is smoothing function why are smoothed lines always crossing can you use a smoothing function in excel to show stacked data? why should smoothed lines always cross?