Type the formula with relative absolute references as needed into the cell. Go to Developer Code Macros. Notice a couple of things.
First we choose the sheet on which the event will occur.
Type the following code into the module sheet. I find its much easier to enter a formula into a cell than to type the corresponding formula in VBA. The values also changed because of the nature of the RANDBETWEEN formula as it changes along with any change done to the workbook. Make sure your formula cells and macro are both selected.