Does the male stock market investor earn signifi cantly more than the female stock market investor? One study by the New York Stock Exchange showed that the male investor has an income of $46,400 and that the female investor has an income of $39,400. Suppose an analyst wanted to ‘prove’ that the male investor earns more than the female investor. Th e following data represent random samples of male and female investors from across the United States. Th e analyst uses the Mann–Whitney U test to determine whether the male investor earns signifi cantly more than the female investor for   0.01. What does the analyst fi nd?

Male Female $50,100 $41,200 47,800 36,600 45,000 44,500 51,500 47,800 55,000 42,500 53,850 47,500 51,500 40,500 63,900 28,900 57,800 48,000 61,100 42,300 51,000 40,000 31,400