Fill Simple...

Selecting Fill Simple from the Tools -> ZRandom menu will show this dialog box:

Options

Between 0 and 1

Select this option if you want to the random numbers to be between 0 and 1.

Between X and Y

Select this option if you want to generate whole numbers between a minimum (X) and a maximum (Y) value.

Unique numbers in each column

Check this option to prevent duplicates from occuring vertically.

Output Range

The coordinates of the cells that should be filled. This field will be prefilled with the coordinates of the selected cells.