Educational testing companies provide tutoring, classroom learning, and practice tests in an effortto help students perform better on tests such as the Scholastic Aptitude Test (SAT). The testpreparation companies claim that their courses will improve SAT score performances by an averageof 120 points (The Wall Street Journal, January 23, 2003). Aresearcher is uncertain of thisclaim and believes that 120 points may be an overstatement in an effort to encourage students totake the test preparation course. In an evaluation study of one test preparation service, the researchercollects SAT score data for 35 students who took the test preparation course and 48 studentswho did not take the course. The file named SAT contains the scores for this study.a. Formulate the hypotheses that can be used to test the researcher’s belief that the improvementin SAT scores may be less than the stated average of 120 points.b. Using a .05, what is your conclusion?c. What is the point estimate of the improvement in the average SAT scores providedby the test preparation course? Provide a 95% confidence interval estimate of theimprovement.d. What advice would you have for the researcher after seeing the confidence interval?
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