Can people who are lactose intolorent eat frozen yogurt?

Up to a point. Most frozen yogurt not high in live cultures, bacteria that break down lactose (milk sugar). Most can eat some dairy without symptoms, gas, bloat, cramps, loose stool. Can always take lactase tabs beforehand; eat as part of a mixed meal helps too.
Depends. Yogurt, frozen or otherwise has lactose in it. It would depend on the serverity of lactose intolerance and amount of yogut consumed. There would no harm in trying small amounts and gradually increasing the amount to a tolerable level.