8. To study the effects of unemployment on the divorce rate, a sociologist selected a random sample of unemployed people from the local unemployment agency and sample of employed people from his graduation class. He then compared the divorce rates for the two groups. This is an experiment observational study (circle one) 9. An educational software company wants to compare the effectiveness of its computer animation for teaching biology with that of a textbook presentation. The company gives a biology pretest to high school juniors, then divides them into two groups. One group uses the animation, and the other studies the text. The company retests all students and compares the increase in biology test scores in the two groups. This is an experiment observational study (circle one) 10. Determine whether each of the following is a statistic or a parameter. After checking computer records for every commercial movie made during a certain year, the longest running time is found to be 187.5 minutes. A recent survey of 200 college career centers reported that the average starting salary for petroleum engineering majors is $83,121