The nonequivalent comparison group design can yield several possible outcomes. In one scenario, the experimental group scores higher than the control group at the start of the experiment, and only the experimental group's scores increase from pretesting to posttesting. This could reflect an influence of the independent variable. However, it could also reflect:
a) a local instrumentation effect.
b) a attrition effect in the control group.
c) simply that the experimental group was studied for a longer time period than the control group.
d) selection-maturation effect.

Griffin correctly concludes that the coordinate pair for the russian federation is an influential point, because removing the russian federation from the relationship will significantly change the trend of the regression line. is an influential point, because removing the russian federation from the relationship will not significantly affect the estimated coefficient of determination of the regression line. is not an influential point, because the russian federation does not have the highest cvdir of all 1111 nations in the scatterplot. is an influential point, because removing the russian federation from the relationship will not significantly affect the estimated slope of the regression line. is not an influential point, because the russian federation has a positive residual in the least-squares linear regression.