Research results suggest a relationship between attending pre-school and average high-school grades. To test if this is true, you decide to conduct an Independent Samples T-test on two groups of students n = 9 in each group with the first group having attended pre-school and the second group not attended pre-school. For the test, you decide to do a two-tail test with an alpha of = 0.05 to test the Ho 12 = 0. The scores for the pre-school group are: 86, 87, 91, 97, 98, 99, 97, 89, and 92. The scores for the non pre-school group are: 90, 89, 82, 83, 85, 79, 83, 86, and 89. What is the obtained t value for this test? O 4.67 O 3.16 O 2.72 O 3.75