You believe that requiring students to attend a series of presentations on study skills will improve their grades. you are concerned that boys and girls might react differently to such a series, and that students in grades 9 and 10 might react differently than those in grades 11 and 12. you set up an experiment involving 100 students in ninth and tenth grade and 100 students in eleventh and twelfth grade. (assume there are equal numbers of girls and boys in each grade.) you intend to measure improvement based on pre- and post-treatment grade-point averages. a describe the design of an experiment to you determine if a set of presentations on study skills is effective in improving grades. b suppose you have 50 students and need to assign them to two groups of equal size. describe a randomization procedure that would achieve this. c suppose you have 50 students and need to assign them to two independent groups. describe a randomization procedure that would achieve this. d describe an appropriate method of analysis for the data you collect from this experiment.