... Difference1 0.40 0.37 -0 .032 0.37 0.14 -0 .233 0 .56 0.40 -0 .164 0.63 0 .50 -0 .13Start of Impact 5 0.33 0.26 -0 .076 0. 45 0.22 -0 .23Mean DifferenceBefore -0 .138After -0 . 150 Figure 6.3 Results ... Table 6.2, and plotted on Figure6.3. The mean difference (impact - control) for times 1 to 4 before theaerial drop is -0 .138. The mean difference after the drop for times 5 and 6 is -0 . 150 , which ... called a control-treatment paired (CTP) design (Skalski and Robson, 1992, Chapter 6),or a before-after-control-impact-pairs (BACIP) design (Stewart-Oatenet al., 1986). Sometimes information is...