The Associated Press___ Back to school is a test for teen retailers NEW YORK (AP) â¿¿ Teens are heading back to school, but it's the retailers catering to them that are getting the first test. They're hoping their expanded selections of funky tee shirts and hip-hugging jeans will attract students like Dale Gibson, 15, who struggles to find trendy clothes in their stores. Ditto for Danielle Martinez, 14, who thinks their merchandise is dull. Same goes for Rochelle Wilson, 19, who stopped shopping them altogether. The "Big Three" teen merchants Abercrombie & Fitch, Aeropostale and American Eagle once defined fashion for fickle teens. But they lost their mojo by not stocking the jeans and tees that their customers covet. So, teens flocked to chains like H&M and Forever 21 that cater to twenty-somethings with up-to-the minute trendy styles that they can mix and match. Now, as the down economy batters both teens and their parents, teen clothing chains are having mixed success as they try to lure young people back into their stores by offering more of the things they love __ boot cut jeans, fleece bottoms and accessories. ___ Service firms grew at slightly faster pace WASHINGTON (AP) â¿¿ Service firms that employ 90 percent of the U.S. work force expanded at a slightly faster pace in August. But the sector remains too weak to help an economy that is barely growing and struggling to create jobs. The Institute for Supply Management said Tuesday that its index for service companies rose to 53.3 in August, up from 52.7 in July. Any reading above 50 indicates expansion. The service sector includes everything from restaurants and hotels to health care firms and financial service companies. It has grown in all but one month over the past two years. The index reached a five-year high of 59.7 in February.