On April 15, 1995, about 2330 central daylight time, a Cessna 172H, N3835R, registered to Vickie C. Hall, operating as a 14 CFR Part 91 personal flight, experienced a total loss of engine power and crashed in the vicinity of Hattiesburg, Mississippi. Visual meteorological conditions prevailed and a VFR flight plan was filed. The airplane sustained substantial damage. The private pilot and two passengers were not injured. The flight originated from Lafayette Municipal Airport, Lafayette, Tennessee, about 4 hours 15 minutes before the accident. The pilot stated he initiated an en route descent from 4,500 feet agl, turned the carburetor heat on and then turned it back off. He continued his descent to 2,000 feet agl, reduced power, turned the carburetor heat on, and the engine quit. An engine restart was attempted with negative results, and the airplane collided with a sewage treatment dike during the forced landing. Review of the probability carburetor icing chart revealed that the engine could encounter serious icing at glide power based on the weather observation at the time of the accident.