CBS Inc. yesterday sent a letter to its stockholders attacking Fairness in Media for attempting to change the content of CBS' news broadcasts to reflect the group's "partisan views."

The attack came on the eve of a meeting scheduled in New York this afternoon between CBS executives and Wall Street analysts.

FIM, a conservative group supported by Sen. Jesse Helms (R-N.C.), has said it will try to gain financial control of CBS to end what it calls the network's "liberal bias." CBS has vowed to fight FIM's attempt to gain control.

Industry sources, in the meantime, said FIM and Helms have held discussions recently with Cable News Network founder Ted Turner. Over the past several years, Turner has expressed interest in acquiring CBS or another network. One one occasion two years ago, Turner approached CBS directly and proposed a combination of his company with CBS. CBS rejected the proposal.

CBS has subpoenaed Turner in an attempt to determine whether he is working with FIM on a takeover attempt.

"While it has not yet done so, FIM has indicated that it is considering nominating director candidates or proposing shareholder resolutions at the annual meeting," CBS said in a letter to shareholders from Chairman Thomas H. Wyman.

"Your board of directors firmly believes that FIM's charges are unfair and unwarranted, and that FIM's campaign is but an attempt to change the content of CBS news reporting to reflect FIM's own partisan views," the letter said.

". . . While your board regrets the cost, both in money and executive time, which are a necessary part of responding to FIM's efforts, it believes such costs are a small price to pay to protect the reputation which CBS News has earned through years of careful, timely and objective reporting.

" . . . the public interest in a free and independent press would be ill served by the interference with the news reporting process which FIM threatens," the letter said.