申論題

1. A recent report claims that college non-graduates get married at an earlier age than college graduates. To support the claim, tandom samples of size 100 were selected from each group, and the mean age at the time of marriage was recorde(D) The mean and standard deviation of the college non-graduates were 21.6 years and 3 years, respectively, while the mean and standard deviation of the college graduates were 23.2 years and 4 years, respectively. To test the claims of the report at the 0.05 level of significance, the figure of the appropriate test statistic is__________.