Samuel Lubell, 76, an author, journalist and noted public opinion analyst who also had been a teacher and government official, died Aug. 16 at a nursing home in Los Angeles after a stroke. He lived in Los Angeles.

From the mid-1940s to the mid-1970s, Mr. Lubell analyzed public opinion surveys and examined everything from election returns and birth records to population shifts in an effort to find out why Americans voted as they did. He also went into the field, not only observing crowds and candidates, but also knocking on doors and asking people questions.

He did not use polls to predict elections as much as he did to explain why the vote had gone as it did. He was a pioneer in the technique of picking "key" precincts that, carefully examined, would reveal something about America as a whole. Along the way, he became that rare breed, the scholar-reporter.

He examined not only personalities but also social and economic forces. His reporting showed the importance of economics on voting and predicted and tried to explain the passions brought to politics by civil rights. He also examined the "new isolationism" in politics and the "campus revolt" of 1960s. His tools were his voter interview-interpretation technique and his own historical perspective.

Over the years, he contributed articles to the nation's leading newspapers and magazines and also reported for radio and television networks. He was the author of six notable books, ranging from "The Future of American Politics" (1952) to "The Hidden Crisis in American Politics" (1970). Mr. Lubell had taught at American, Columbia and Harvard universities.

Writing in The Washington Post in 1970, columnist David Broder said, "Better than any other contemporary journalist, Samuel Lubell has constructed from the insights of his own voter interviews, rigorous analysis of election returns and sensible political theorizing, an interpretation of contemporary American politics meaningful both to the scholar and the everyday newspaper reader.

Mr. Lubell came to this country from his native Poland when he was an infant. He grew up in New York City and was educated at the City College of New York and Columbia University's journalism school. He wrote obituaries for the Long Island Daily Press before coming to Washington in the mid-1930s. He spent about a year at The Washington Post, where he wrote for the "Federal Diary" column.

He then worked for the Richmond Times-Dispatch and the Washington Herald, and contributed articles to the Saturday Evening Post. During World War II, he was an aide to Bernard M. Baruch, first as general secretary of the Rubber Survey Committee (also known as the Baruch Committee) and then with the Office of War Mobilization.

After the war, he spent a short time as European correspondent with the Providence Journal, then made his mark as a free-lance journalist. His work began appearing in Harper's, Commentary, Collier's, the American Mercury and the Nation, as well as the Saturday Evening Post.

His "Future of American Politics" helped popularize the idea that we are a people of shifting voting tendencies, loyal to no political party and composed of diverse minorities. His book pointed out that there was no longer an effective majority in the nation. He saw both major political parties ever struggling to align their interests and become truly national forces.

Mr. Lubell was a member of the National Press Club. He retired in 1976 and moved to California.

Survivors include his wife of 46 years, the former Helen Sopot of Los Angeles; two sons, and a sister.

ISABEL PIMENTEL,

91, a Washington area resident since 1957 who had owned a high-fashion boutique in Venezuela, died of a pulmonary embolism Aug. 20 at Alexandria Hospital. She lived in Falls Church.

Mrs. Pimentel was born in Caracas, Venezuela. She moved to the United States in 1957 and settled in the Washington area.

She was a member of Alianza Ibero-Americana, a social and civic organization. She served on the board of the Pan-American Liaison Committee Organization, which named her Woman of the Year in 1979.

Her husband, Heraclio Guerra, died in 1924. Survivors include one son, Vincent Guerra of Arlington; three granddaughters, and six great-grandchildren.