Researchers wanted to explore self-esteem in adolescent boys and girls. They used a 5 point Likert-type self-esteem inventory; 1=strongly disagree and 5= strongly agree. What if their results yielded the following: t=1.71, d=.90. What statistical test did the researchers use to determine if there was a statistically significant difference in levels of self-esteem between the boys and girls? What was the purpose of calculating a Cohen's d? When is a Cohen's d calculated? Interpret d=.90. What does it mean in this example?