The vibration of the vocal cords is called

When an organism uses insight, it ____

a. ?forms associations between actions and consequences b. watches the actions of others c. ?learns that two stimuli usually tend to occur together d. ?thinks through possibilities, then reaches a sudden understanding

The Pearson correlation between X1 and Y is r = 0.40 and SSY = 100. When a second variable, X2, is added to the regression equation, we obtain R2 = 0.25. How much additional variability is contributed by adding the second variable as a predictor compared to using X1 alone?

A) ?9 points B) ?15 points C) ?25 points D) ?40 points