Four Perspectives on . . .

17

premessage fear, acceleration, velocity, and deceleration respectively. Although all four are

nonsignificant at p < .05, the significance test alone is not a convincing means of assessing a no-

difference hypothesis. Rather, a power analysis is needed. With an N of 361 and two-tailed alpha

of .05, power is .46 for small correlations (i.e., .10) and greater than .99 for moderate (i.e., .30)

and large correlations (i.e., .50) (Cohen & Cohen, 1983). Thus, while we cannot rule out a small

relationship, H3 is clearly supported for moderate to large associations.

H4-H6: Acceleration, Velocity, and Deceleration Perspectives

H4-H6 predicted positive associations between persuasion and acceleration, velocity, and

deceleration respectively. And, as Table 2 shows, the simple correlations support all three

predictions. They are .18, p < .01, for acceleration, .18, p < .01, for velocity, and .15, p < .01, for

deceleration. However, a method was needed that allowed more stringent comparisons between

perspectives. Consequently, we turned to regression analysis. For each analysis, the change in

likelihood of obtaining a flu vaccination served as the dependent variable. The independent

variables were entered in two blocks. The first block contained one of the three fear variables,

whereas the second block contained a different fear variable that was being contrasted with first.

Due to collinearity among the fear indices, only two tests per equation were conducted. We ran

each equation twice, in each case reversing the order of entry of the two variables that were to be

contrasted. In this way, each predictor was given the opportunity to consume as much variance in

the dependent variable as possible prior to its competitor. Comparing the results obtained from

different entry orders helped to clarify the contribution of each perspective.

Table 3 presents the results of the regression analyses in three parts.

2

In the upper portion

of the table, the acceleration and velocity perspectives are compared. Inspection of the R

2

)

values