TV RATINGS

Dull but true--last week’s top five Nielsen winners were the usual collection of NBC comedies; three of the sitcoms have changed positions occasionally in recent weeks but “The Cosby Show” and its spinoff, “A Different World,” consistently lead the pack. Weekly network averages: NBC, 16.3 rating/27 share; CBS, 13.8/23; ABC, 12.6/21. Evening news ratings: CBS 12.1, NBC 11.2, ABC 11.1. (One Nielsen point equals 886,000 homes; “share” refers to the percentage of households watching a particular program.) The complete Nielsens appear on Page 12.

* CBS’ “Candid Camera Christmas Special,” featuring the classic show’s original host Allen Funt, replaced “Magnum, P.I.” Wednesday at 9 p.m. and won the time slot, becoming one of this holiday season’s few successful Christmas specials.

SHOW POINTS SHARE WEEK 1. The Cosby Show 29.3 46 12/20 (NBC) 30.0 47 12/13 2. A Different World 26.9 42 12/20 (NBC) 27.9 43 12/13 3. Cheers 25.5 40 12/20 (NBC) 23.1 36 12/13 4. Night Court 25.0 40 12/20 (NBC) 22.9 36 12/13 5. Golden Girls 22.0 40 12/20 (NBC) 21.0 37 12/13 * Candid Camera Special 17.7 27 12/20 (CBS) ---- -- -----