A fund manager reported a 2% mean quarterly return over the past ten years for its entire base of 250 client accounts that all folkw the same investment strategy A corvuitant employing the manager for 45 client accounts notes that their mean quarterly returns were 0.25% less over the same period. The consultant tests the hypothesis that the return disparity between the returns of his clients and the reported returns of the fund manager's 250 client accounts are significantly different from zero Assuming normally distributed populations with unknown population variances, the most appropriate test statistic is O at test of the difference between the two population means O a paired comparisons t-test an approximate t-test of mean differences between the two populations O an approximate F.test of mean differences between the two populations