TESTS FOR NON-GAUSSIAN STATISTICS IN THE DMR 4-YEAR SKY MAPS

We search the high-latitude portion of the COBE Differential Microwave Radiometer (DMR) 4 yr sky maps for evidence of a non-Gaussian tempera ture distribution in the cosmic microwave background. The genus, three -point correlation function, and two-point correlation function of tem perature maxima and minima are all in excellent agreement with the hyp othesis that the CMB anisotropy on angular scales of 7 degrees or larg er represents a random-phase Gaussian field. A likelihood comparison o f the DMR sky maps to a set of random-phase non-Gaussian toy models se lects the exact Gaussian model as most likely. Monte Carlo simulations show that the two-point correlation of the peaks and valleys in the m aps provides the greatest discrimination among the class of models tes ted.