Could you assist me with this question pls?

4. Some nurses in county public health conducted a survey of women who had received inadequate prenatal care. They used information from birth certificates to select mothers for the survey. The mothers selected were divided into two groups: 14 mothers who said they had five or fewer prenatal visits and 14 mothers who said they had six or more prenatal visits. Let X and Y equal the respective birth weights (in ounces) of the babies from these two sets of mothers, and assume that the distribution of X is N(ux, ?) and the distribution of Y is N(uy, o?): (a) Define the test statistics and critical region for testing Ho : ux - py = 0 against Hi : Hx - My