Dental anxiety study
Does recalling a traumatic dental experience increase your level of anxiety at the dentist's office? In a study published in Psychological Reports (August 1997), researchers at Wittenberg University randomly assigned 74 undergraduate psychology students to one of three experimental conditions. Subjects in the ‘‘Slide'' condition viewed 10 slides of scenes from a dental office.
Subjects in the ‘‘Questionnaire'' condition completed a full dental history questionnaire; one of the questions asked them to describe their worst dental experience. Subjects in the ‘‘Control'' condition received no actual treatment. All students then completed the Dental Fear Scale, with scores ranging from 27 (no fear) to 135 (extreme fear). The sample dental fear means for the Slide, Questionnaire, and Control groups were reported as 43.1, 53.8, and 41.8, respectively.
(a) A completely randomized design ANOVA was carried out on the data, with the following results: F = 4.43, p-value
(b) According to the article, a Bonferroni ranking of the three dental fear means (at α = .05) ‘‘indicated a significant difference between the mean scores on the Dental Fear Scale for the Control and Questionnaire groups, but not for the means between the Control and Slide groups.'' Summarize these results in a chart that connects means that are not significantly different.