CHARLOTTE, N.C. -- They studied just enough to pass their "boring" classes. They didn't like school and spent their evenings playing sports or watching television instead of doing their homework.

They were the kind of average students who usually are forgotten or overlooked in public schools -- but not at South Mecklenburg High School. A novel program in its second year provides 150 sophomores and seniors with a more personal atmosphere and smaller class size designed to motivate C students to do better.

While courses for exceptional students or slow learners are common, the school is believed to be the first in the country to tailor special courses for students of middling abili- ty.

"Never since I've been a principal have we directed our monies to average or below-average kids," said Betty Riddle of South Mecklenburg, which already had three programs for above-average students -- advanced placement, academically gifted and advanced.

"We've sort of left out the middle folks. We haven't given them the extras," Riddle said.

"There is a whole big percentage of a student body that has passed through high school and hasn't connected with anybody. They're not in the band, on the debate team or athletics," Riddle said. "They don't feel successful, and they're not successful."

Improving the performance of this group has become of increasing concern to educators because of fears the United States will not remain economically competitive unless it not only produces first-rate scientists and original thinkers but also raises the educational level of its entire work force.

"What our best students can achieve now, our average students must be able to achieve by the turn of the century," the National Governors' Association declared in February in setting six ambitious goals for the year 2000.

South Mecklenburg has yet to get those kind of results. But teachers in the program said they believe they have interested some students in school for the first time and inspired them to work harder and earn better grades. And students praise teachers for giving them more individual attention and varying classroom routine.

A preliminary review by school officials shows at least 64 of 74 seniors in the program last year improved their grades. The average rose from a C to just above a C. The most improved student went from a C-plus to a B average.

Teachers say a number of students have been motivated to continue their educations beyond high school, and several who appeared at risk of dropping out did not. All but one senior in the program graduated last spring, while the one exception completed studies over the summer.

"It's one of the most successful things we've ever done," said Margaret Griehsbach, assistant superintendent for curriculum and staff development for the Charlotte-Mecklenburg schools.

Lisa Farnick, now a freshman at Western Carolina University, described herself as a lackadaisical student who was given C's and D's before entering the program at South Mecklenburg last year.

"I knew I could make A's and B's, but I was lazy. I wasn't motivated," she said. "I didn't like school."

If a teacher called on her in class, she recalls, "I'd try to give the answer, but I wouldn't raise my hand or anything." At night she would study "probably not even an hour, even when it was time for tests," but would spend time swimming, playing tennis and watching TV for a couple of hours.

Three weeks into the program, Farnick said she "really buckled down and studied," usually for three hours a night. Later, A's and B's provided evidence of an academic turnaround that astonished her parents.

"She would come home, watch about 15 minutes of TV and then disappear for three or four hours. We would say, 'We waited 12 years for this,' " said Kay Farnick, a nurse, referring to herself and her husband, an accountant.

Lisa Farnick can't say herself what it is that made her more interested in school, but her mother has some ideas. "How they touch these youngsters, I guess, is the individual attention," she said, and the fact that students who are selected have no real discipline problems.

The gains made by students like Lisa Farnick persuaded school officials to extend the program this year to ninth-graders at West Mecklenburg High and to 10th-graders at South Mecklenburg.

The program is called the school within a school, a generic name that tends to minimize any stigma. Still, when first contacted about enrolling, students and their parents usually think "special" means special education. "The first question asked by most parents is: 'Is this a class for slow learners?' " said Mary Hammond, a biology teacher and leader of the team of teachers for the 10th-grade program.

Students are selected for the program if they scored between the 35th and 80th percentiles on the California Achievement Test, and if previous teachers believe they have performed below their potential. Students with serious discipline problems are screened out.

The teachers are handpicked, according to Riddle, on the basis of their command of the subject and the ease which with they relate to students. She wanted to create an environment like a middle school, where classes would be small enough for teachers to get to know and develop a personal interest in their students.

Other educators have recommended dividing large schools into smaller units to make them more personal. With 1,500 students, South Mecklenburg is one of the biggest high schools in North Carolina. Most of its students are white and middle- or upper-class, and about one-fourth are working-class black students bused under a desegregation plan. The mix of average students in the program is similar.

A four-member team instructs 85 seniors for a block of four periods in English, world history, mathematics and computer applications. Another three-member team has three periods to teach biology, math and English to 66 10th graders. Both groups of students share a counselor.

Class size in the program has averaged in the low twenties, compared to more than 30 in other classes. The minimal extra costs include the salary of an extra counselor and several hundred dollars for instructional supplies.

Students said they took more interest because the smaller classes allowed more individual attention.

"The classes aren't so big," said Shawn Mack, a 10th grader. "In other classes, you want to ask a question so bad, but they call on the smarter guy. You don't get a chance to express yourself in the education system."

Johann Grier, who graduated from the program last year, said it was "the first time I ever felt comfortable talking to a teacher."

The content is the same as in regular courses, but instruction is not. Riddle has authorized the teams to "organize their day in any way they want to." They have taught classes jointly, organized field trips and deviated from the standard 55-minute period. Education reformers have frequently proposed giving teachers the flexibility to make such professional judgments.

During a recent week, English teacher Les Browne and computer instructor Alverette Callaway collaborated for an interdisciplinary lesson in which seniors corrected one essay and typed another on computers. That day the senior program had three periods of 75 minutes each, rather than four of 55 minutes.

Steve Blanton had his senior world history class write letters, clip newspaper features and mail them to U.S. military personnel in Saudi Arabia. He injected a cultural lesson when one student clipped a picture of the new Miss America. "That picture looks pretty tame to us, but in Saudi Arabia she might as well be buck-naked. She's got her arms and legs showing," Blanton warned.

"The old idea -- of standing up, lecturing, giving a test -- we all know isn't working for the majority of kids," said Hammond, the biology teacher.

Students said the classroom variety made them enjoy learning. "Classes seem to move faster. They give fun activities for us to do. It's not the everyday," said Kent Linkner, a senior.

"I wasn't too thrilled about going to school my sophomore and junior year," recalled Jill Onley, 18. "I started in the program, and it just made you want to go to school. Everything we did was different from normal classroom study because everything we did was different every day."

Onley, the most improved student last year, currently waits on tables at a local restuarant, but plans to enroll at a state university next year. She had wavered about going to college and decided on that goal only after entering the program, she said.

"Jill had absolutely no direction in her life and when she found some, she blossomed," said Browne, who was her English teacher. "I believe Jill would have been a dropout if she had not been in the program."

Many of last year's students planned to enroll in community colleges or state universities in North Carolina other than the main campus in Chapel Hill. The colleges are not academic powerhouses, but Riddle sees in them the higher aspirations of a group of average students.

"Do I think we're going to make some Phi Beta Kappas with this group?" Riddle said. "No. But I do think we can keep them in school and get them in a position where they make some choices about what they're going to do when they leave school, and have more choices."