10.34 Independent-sample t tests and “Blinded with Science”: Researchers studied the effects of learning about the effectiveness of a new medication (Tal & Wansink, 2016). Some participants heard information about the medication; others heard the same information and saw a graph that depicted the data they had heard about. Thus, the two groups had identical information. Participants rated the effectiveness of the medication on a scale of 1–9, with 9 indicating a higher level of effectiveness. The researchers reported: “Participants given graphs expressed greater belief in the claims, rating the medication as more effective (6.83 of 9) than did participants given verbal description only (6.12 of 9): t(59) = −2.1, p = 0.04” (p. 4). The researchers titled their paper “Blinded with Science” because the mere presence of a scientific cue—a graph—altered perceptions of the medication.

a. What kind of t test did the researchers use? Explain your answer.

b. How do we know this finding is statistically significant?

c. How many participants were in this experiment?

d. Identify the means of the two groups.

e. What additional statistics would it have been helpful for the researchers to include?