9.47 Cheating and a single-sample t test: Participants in a study (Chou, 2015) aimed at understanding cheating behaviors were asked to flip a coin 20 times and report—on the honor system—how many heads they received. The more heads, the more entries they would receive for a raffle for money. The catch? Some of them were randomly assigned to sign their name in ink on paper—old-school. Others were randomly assigned to check a box or type their name. Does signing your name make you more honest? If participants did not cheat, the probability of getting heads would be 50%, the population mean. The researchers reported that “a one-sample ttest … revealed that those who signed electronically reported getting significantly more heads than the statistical average (M = 56.17%, SD = 16.12, t(207) = 5.52, p < 0.001)” but that participants who signed on paper in ink did not exhibit a significant effect “( M = 51.61%, SD = 22.77; t(61) = 0.55, p = 0.57).”

a. What does the number 207 indicate about the number of people in this particular sample?

b. What does the number 16.12 tell us about this particular distribution?

c. These findings do not give us any information about the effect size. Why would we want to know the value of Cohen’s d?

d. Explain this finding in your own words.