*9. The Roper Organization (1992) conducted a study as part of a larger survey to ascertain the number of American adults who had experienced phenomena such as seeing a ghost, “feeling as if you left your body,” and seeing a UFO. A representative sample of adults (18 and over) in the continental United States were interviewed in their homes during July, August, and September 1991. The results when respondents were asked about seeing a ghost are shown in Table 12.10.

*a. Find numbers for each of the following:

i. The percentage of the younger group who reported seeing a ghost ii. The proportion of the older group who reported seeing a ghost iii. The risk of reportedly seeing a ghost in the younger group iv. The odds of reportedly seeing a ghost to not seeing one in the older group

b. What is the relative risk of reportedly seeing a ghost for one group compared to the other? Write your answer in the form of a sentence that could be understood by someone who knows nothing about statistics.

c. Repeat part b using increased risk instead of relative risk.

CHAPTER 12 Relationships Between Categorical Variables 235 Table 12.10 Age and Ghost Sitings Reportedly Has Seen a Ghost Yes No Total Aged 18 to 29 212 1313 1525 Aged 30 or over 465 3912 4377 Total 677 5225 5902 Data Source: The Roper Organization, 1992, p. 35.