There are several companies that provide test-preparation programs for a nationwide admissions test. A researcher is sorting through four studies, each of which examines the effectiveness of a different test-preparation program. In each study, the test scores of a control group that didn't receive any special preparation were compared to those of a group that followed the particular test-preparation program. A one-tailed, independent-samples t test (with the assumption of equal variances) was performed in each study to see if the mean for the test-preparation group was significantly greater than the mean for the control group. The table below summarizes the four tests. The subscript "1" refers to a control group, and the subscript "2" refers to a test-preparation group. The value s,, is the pooled sample standard deviation. Note that this value was not reported in one of the studies. Program A Program B Program C Program D x =620 x 610 x =600 X -620 Sample means x2 = 700 X = 690 X, 690 X2 690 Pooled sample standard deviation 5 92 SD- 95 Not reported Sp 98 n = 20 1 =25 1 = 15 1 =15 Sample sizes n, = 20 n, = 25 n, = 15 12 = 15 t test p-value 0.005 0.002 0.039 0.030 (a) Order the programs by their estimated effect sizes (ES) from least to greatest. X 5