The stock market staged a mild rally Friday following what analysts described as an ambiguous report on employment.

Technology issues led the advance in a session of moderate activity.The Dow Jones average of 30 industrials rose 12.83 to 2,304.80, closing out the week with a net gain of 11.18 points.

Advancing issues outnumbered declines by about 8-to-5 in nationwide trading of New York Stock Exchange-listed stocks, with 881 up, 546 down and 525 unchanged.

Volume on the floor of the Big Board came to 156.95 million shares, against 146.53 million in the previous session. Nationwide, consolidated volume in NYSE-listed issues, including trades in those stocks on regional exchanges and in the over-the-counter market, totaled 184.23 million shares.

The Labor Department reported that the unemployment rate declined to 5.0 percent, a new 15-year low, in March, from 5.1 percent the month before. That surprised analysts, who had been looking for a small increase.

By contrast, the data also showed a smaller-than-expected gain of 180,000 in non-farm payroll employment, providing some support for the view that the economy has been slowing since early this year.

Brokers said the overall result was something of a letdown, since many investors had been hoping for a more clear-cut signal that pressures were abating on inflation and interest rates.

But traders also apparently interpreted the data as positive for technology stocks, which have been depressed lately by earnings worries and concern about a possible business slump.

The group got a further boost from Businessland Inc., which said it expected to post record profits for the fiscal quarter ended March 31, citing increased sales of International Business Machines and Apple Computer products.

IBM shares rose 13/4 to 1093/4 and Apple, traded in the over-the-counter market, climbed 13/8 to 373/8. Businessland, up 11/8 at 121/8, ranked among the day's best percentage gainers.

Elsewhere among technology issues, Digital Equipment rose 13/8 to 973/8; Honeywell 23/8 to 731/4; Prime Computer 3/4 to 181/8, and Hewlett-Packard 11/2 to 531/4.

But Control Data fell 11/4 to 213/4. In its annual report, the company said it was studying the possibility of selling some significant assets to satisfy its bankers.

Tyler Corp., which said it was involved in talks about the possible sale of its Reliance Universal business, jumped 11/2 to 9.

L.A. Gear gained 33/8 to 39. The company said it expects to meet analysts' projections of its 1989 earnings.

As measured by Wilshire Associates' index of more than 5,000 actively traded stocks, the market increased $15.68 billion, or 0.54 percent, in value.

The NYSE's composite index of all its listed common stocks added .91 to 166.93.

Standard & Poor's industrial index rose 2.41 to 342.30, and S&P's 500-stock composite index was up 1.87 at 297.16.

The NASDAQ composite index for the over-the-counter market gained 2.51 to 410.71. At the American Stock Exchange, the market value index closed at 330.59, up .51.