Fig. 4

a Percentage of biology majors (black bars, n = 237) and nonmajors (white bars, n = 239) who agree with one of the following statements concerning evolution in science exams: A = I have no problem answering questions concerning evolution, B = science exams should always include some questions concerning evolution, C = do not know enough to say, D = I prefer not to answer questions concerning evolution, and E = I never answer questions concerning evolution. Raw data chi-square = 27.026, df = 4, P ≤ 0.001; asterisks indicate Sign test two-tail pair-wise comparisons P ≤ 0.002. b Percentage of freshman (F), sophomore (So), junior (J), and senior (Sr) biology majors who agree with statements A, B, or C (above) concerning evolution in science exams (D and E were excluded from the analysis because over 20% of their expected values were less than 5). Chi-square of percentage values = 15.316, df = 6, P value = 0.018