"Virginity Pledgers Still Take Sex Risks" explains that "virginity pledges emerged in the early 1990s based on the theory that young people would remain chaste if they had broader community support-or pressure-to remain abstinent." One virginity group called True Love Waits has youths sign a card stating: "Believing that true love waits, I make a commitment to God, myself, my family, those I date and my future mate to be sexually pure until the day I enter marriage." A study published in the Journal of Adolescent Health found that 20% of several thousand youths in a longterm study said they had taken a virginity pledge; some of these were termed "inconsistent pledgers," if their status or responses changed over time. "Almost 7% of the students who did not take a pledge were diagnosed with an STD (sexually transmitted disease), compared with 6.4% of the 'inconsistent pledgers' and 4.6% of the 'consistent pledgers.'"15 The study's author, Peter Bearman, said these differences were not statistically significant, although spokesman Robert Rector from the conservative Heritage Institute said he interpreted the data to mean that young people committed to the abstinence pledge were less likely to become infected.
a. Who believed the differences among sample percentages could be attributed to chance in the sampling process, Bearman or Rector?
b. If Bearman is wrong, is he committing a Type I or Type II Error?
c. If Rector is wrong, is he committing a Type I or Type II Error?
d. Bill Smith, public policy vice president for the Sexuality Information and Education Council of the United States, said, "Not only do virginity pledges not work to keep our young people safe, they are causing harm by undermining condom use, contraception and medical treatment." Which chi-square test is Smith suggesting would have a small P-value: the one for a relationship between pledges and STDs or the one for a relationship between pledges and use of other preventive measures?