investigation found nothing wrong with the plane despite the events .
skywest inc , based in st. george , utah , said the jet landed safely and three passengers received medical attention before being released .
the embraer 175 twin-jet , traveling from chicago to hartford , connecticut , carrying 75 passengers dropped from 38,000 ft to 10,000 ft in three minutes .
the faa said initial information indicated the embraer e170 jet may have had a pressurization problem .
three passengers passed out on board the flight and an additional 15 adults and two children were evaluated upon landing .