21-34. What's the design? Read each brief report of statistical research, and identify a) whether it was an observational study or an experiment. If it was an observational study, identify ( if possible) b) whether it was retrospective or prospective. c) the subjects studied and how they were selected. d) the parameter of interest. e) the nature and scope of the conclusion the study can reach. If it was an experiment, identify (if possible) b) the subjects studied. c) the factor(s) in the experiment and the number of levels for each. d) the number of treatments. e) the response variable measured. () the design (completely randomized, blocked, or matched). g) whether it was blind (or double-blind). h) the nature and scope of the conclusion the experiment can reach. R3.8. People who read the last page of a mystery novel first gen- erally like stories better. Researchers recruited 819 college students to read short stories, and for one story, they were given a spoiler paragraph beforehand. On the second and third story, the spoiler was incorporated as the opening para- graph or not given at all. Overall, participants liked the sto- ries best after first reading spoilers. (Psychological Science, August 12, 2011)