Null and research hypotheses: Using the research studies described in the previous exercise, create null hypotheses and research hypotheses appropriate for the chosen statistical test:

1. Taylor and Ste-Marie (2001)studied eating disorders in 41 Canadian female figure skaters. They compared the figure skaters' data on the Eating Disorder Inventory to the means of known populations, including women with eating disorders. On average, the figure skaters were more similar to the population of women with eating disorders than to those without eating disorders.

1. In an article titled "A Fair and Balanced Look at the News: What Affects Memory for Controversial Arguments," Wiley (2005) found that people with a high level of previous knowledge about a given controversial topic (e.g., abortion, military intervention) had better average recall for arguments on both sides of that issue than did those with lower levels of knowledge.

1. Engle-Friedman and colleagues (2003) studied the effects of sleep deprivation. Fifty students were assigned to one night of sleep loss (students were required to call the laboratory every half-hour all night) and then one night of no sleep loss (normal sleep). The next day, students were offered a choice of math problems with differing levels of difficulty. Following sleep loss, students tended to choose less challenging problems.