The Houston-area unemployment rate dipped to 4 percent in April, down from 4.2 percent in March, the Texas Workforce Commission reported Friday. The local rate is not adjusted for seasonal factors such as major holidays and school schedules, which typically affect hiring and firing patterns. The statewide rate, which is adjusted for those seasonal factors, remained steady at 4.2 percent, the commission said. Texas employers added 1,200 jobs in April.