The federal government would like to test the hypothesis that the average age of men filing for Social Security is higher than the average age of women set using= 0.05 with the following data:

Sample mean: Men= 64.5 years. Women=63.6 years.

Sample size: Men= 35. Women= 39.

Population standard deviation: Men= 3.0 years. Women= 3.5 years.

If Population 1 is defined as men and Population 2 is defined as women, the test statistic for this hypothesis test would be