KAPLAN, an organization teaching people how to prepare for GRE, advertises that it guarantees test scores will increase after participation in its program. Twenty (n=20) students were randomly recruited into the program and take a test before its training. Then all of them took the same test that was given previously. The range of test score is from 200 to 800. What satistical test will you reommend? Set up the statistical hypotheses to be tested assuming you are working for Kaplan company. What test statistic need ot be applied for testing (gve the formula with listing conditions). What is your decision rule when Type 1 error is set at at 0.05?