The House Ways and Means Committee voted yesterday to raise the standard deduction and give an especially large increase to single parents. But it defeated a proposal to raise the personal exemption to $2,000, as President Reagan had proposed in his tax overhaul plan last spring.

The change in the standard deduction, which is used by taxpayers who do not itemize deductions, would significantly reduce the tax burden of lower-income workers, especially those with children.

All actions by the committee, which is slowly moving through a major revision of the tax code, are considered tentative and many are likely to be changed before the committee completes action on the bill.

"Everything is still on the table," said Rep. Robert T. Matsui (D-Calif.).

The committee voted yesterday to raise the standard deduction from $3,670 to $5,950 for a married couple filing jointly, from $2,480 to $3,525 for a single taxpayer and from $2,480 to $4,775 for a single head of household with dependents.

The revised standard deduction would let taxpayers take an extra $500 per child off their income before calculating taxes. It also would be $500 higher for elderly and blind taxpayers.

Rep. Barbara B. Kennelly (D-Conn.) offered the amendment to give the most generous increase to single-parent families. She coupled it with smaller increases for other taxpayers than called for in the bill drafted by Ways and Means Committee Chairman Dan Rostenkowski (D-Ill.), which forms the basis for the panel's deliberations, to keep her amendment from losing revenue.

The committee yesterday rejected a proposal by Rep. W. Henson Moore (R-La.) to raise the personal exemption to $2,000. Reagan has described the proposed increase as one of the key "pro-family" aspects of his tax plan.

Further amendments are expected to alter the exemption, which is now $1,040. All taxpayers are allowed to take exemption for themselves and their dependents.

Committee Republicans and Treasury Department officials pushed hard for the $2,000 exemption, but the amendment was voted down twice in slightly different forms.

The Rostenkowski bill would increase the exemption to $1,500. Unless it is changed by the committee, the $1,500 figure will stand.

The committee also defeated a proposal by Rep. Charles B. Rangel (D-N.Y.) to increase the earned income tax credit, which helps low-income taxpayers offset the cost of Social Security taxes.

The committee is expected to continue trying to shift the tax burden away from the poor, however. Rep. Richard A. Gephardt (D-Mo.) said yesterday he plans to propose a series of amendments during the tax-writing process that would have the effect of making various tax deductions worth less to taxpayers in high tax brackets.

Gephardt said he will propose making the personal exemption a credit rather than a deduction. That means taxpayers could subtract the amount from the taxes they owe, rather than from their income.

Deductions are worth more to wealthier taxpayers. A taxpayer in the 50 percent bracket, for example, saves 50 cents in taxes for every $1 in deductions, while a person in the 11 percent tax bracket saves just 11 cents in taxes for each $1 in deductions. CAPTION: Picture, Rep. W. Henson Moore . . . proposal to raise exemption to $2000 fails.