L for Leave-L-Out Use the field/slider to specify the number of observations to hold out. Note: If you specify 0, no cross validation is performed. To Specify the Number of Observations to Leave Out: Select L for Leave-L-Out as the Hold-Out Size, Specify as:. Either type the desired number of observations in the text field or move the slider to the right or to the left to specify a value. Tip: To change the scale of the slider, right-click on the slider and select Rescale Slider from the pop-up menu. Change the upper and/or lower boundaries in the window that appears, to rescale the slider and click OK.