POLLSTERS USED TO UPS AND DOWNS.(MAIN)

Byline: THOMAS HARGROVE Scripps Howard

Recent public opinion polls suggest the presidential race is not a campaign but a roller coaster ride.

Witness polls that showed Al Gore enjoying an 11-point advantage Wednesday only to see George W. Bush roar past him with an 8-point lead by Saturday.

Is the race really this fluid?

``In our experience, this is normal. The whole reason we have debates and the candidates spend millions of dollars on advertisements is to change people's minds,'' said Frank Newport, editor in chief of the Gallup Poll. ``It would be unusual to us if nothing changed.''

Gallup reported that the vice president was …