How to set a date-based x-axis in Numbers with incomplete data?
You can make a plot using your x,y values and then change the x-axis to be what you want. maybe your x values only run from 0 to 5 but y-data has x-values from 0-50. Click on your plot and then click on the axis tab in the right sidebar. From here you can select the x-axis and on the panel that appears you can input the min and max x-values you wish to use. See figure below.