A production manager wants to determine possible differences between the employee absence rates for the day versus the evening shifts. The number of absences per day is recorded for both the day and evening shifts for n5100 days. It is found that the number of absences per day for the evening shift xE exceeded the corresponding number of absences on the day shift xD on 63 of the 100 days. Do these results provide sufficient evidence to indicate that more absences tend to occur on one shift than on the other or, equivalently, that 

P(x > xD) 1/2? xD)=1/2?