Less than 24 hours after President Carter's speech Sunday night, the first scientific sampling of national reaction shows the address apparently supplied the major public opinion boost the White House had hoped for.

A survey by Roger Seasonwein Associate, a New York-based polling firm, indicates that after the address, 30 percent of the voting-age public thought the president was doing a "good job," compared with only 21 percent who thought so as of noon Saturday. Thirty-six percent thought Carter was doing a "fair" job after the Sunday speech 26 percent thought he was handling his job poorly, and 8 percent "didn't know."

Results of this poll, completed at 8 last night, show two additional public opinion victories for Carter in the wake of the Sunday night speech and the high drama it entailed. Fifty percent of the people in the poll who had watched the speech said it improved their opinion of the president, while only 3 percent of the viewers said it gave them a worse opinion of Carter; 42 percent said the speech had little or no effect on their opinion of the president.

Also, 52 percent of the sample said they favor the president's new energy proposals. Only 10 percent of those polled said they did not favor the proposals, while 38 percent were neutral or had no opinion.

The nine percentage-point increase in the president's job approval rating is almost as great as his jump in the polls immediately after the Mideast summit at Camp David last September. After the summit with the leaders of Israel and Egypt Carter's rating rose to 39 percent from 29 percent a month before.

Carter's latest ratings jump still puts the president's job approval rating at only 30 percent, indicating that although he may now be on the way up politically, the president has a long way to go.

Events leading up to the speech, from the dramatic cancellation of an earlier planned address to the hastily convened Camp David "domestic summit," apparently gave Carter the large audience he was seeking. Of the 1,000 persons polled nationwide, 74 percent watched either the televised address Sunday or some recounting of Carter's speeches yesterday on the news.

The one negative finding in the poll was that only 35 percent of those viewers felt the president's new energy proposals represented a major policy change; half the viewers saw no energy policy change, and the rest had no opinion.

The pollsters asked the sample audience whether they thought President Carter is doing a good job, a fair job, or a poor job.

Results last night:

Good job 30

Fair job 36

Poor job 26

Don't know 8

Results noon Saturday:

Good job 21

Fair job 38

Poor job 34

Don't know 7