An Article in a Journal Examined the Attitudes of Three $1 =$

An article in a journal examined the attitudes of three groups of professionals on the condition of the environment, and quantified their responses on a seven-point scale ( $1 =$ no problem to 7 = disaster very likely) . The mean scores for the groups are: A: $4.30$ , B: $4.07$ , and C: $4.05$ . Using an experimentalwise error rate of $\alpha = .05$ , Tukey's minimum significance for comparing means is $0.21$ . Use this information to conduct a multiple comparisons of the means.

A) There is no significant difference in any of the means.
B) All means are significantly different.
C) The highest mean differs significantly from the other two, but there is no significant difference in the other two means.
D) The lowest mean differs significantly from the other two, but there is no significant difference in the other two means.