WHAT'S THE DIFFERENCE: HOW MEN AND WOMEN COMPARE, compiled by Jane Barr Stump, Ph.D. (Morrow: $12.95). More than 1,000 entries contrast men and women in a wide range of categories, from occupational information to behavioral and physiological data. In her Foreword, Dr. Stump writes: "Our descendants . . . will view (us) with a sense of sadness and compassion because they will know more about . . . what it means to be human." They may also find this book more meaningful. On the plus side, it gives some vivid reminders of just how much job and wage discrimination that women still face in the mid-1980s: In the "over $75,000 income bracket men outnumber women 37 to 1; men with 8th grade educations earn more on average than women with college degrees." The book provides evidence that indicates women are more humane than men: Men like sexual and ethnic jokes more than women do; men commit 90% of the violent crimes. On the other hand, an observant 10-year-old realizes that almost all (97% plus) truck drivers, auto mechanics, pilots and plumbers are male and that almost all dressmakers, secretaries and kindergarten teachers are female. Even more obvious facts are soberly passed along, such as--"male shoulders are broader and stronger than the female's" and "men are about 10% bigger than women." Finally, you can learn whether men or women have hiccups more often and what percentage of the two sexes, when surveyed, said they would consent to sexual relations with a stranger for $1 million.