by the preview screen...do you mean the screen as shown in the bottom left of the two bottom images in this link?
Using graduated symbols—Help | ArcGIS for Desktop
If so, that is a preview of what things would look like if the data were of the correct type and the conditions for a match were correct. Then when you hit Apply etc, your map would be as advertised. Somewhere in your description, this obviously didn't happen, so could you elaborate on the data type etc