What kind of research design or methodology allows us to make causal conclusions by demonstrating that a change in one variable causes a change in another variable?

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.