You are performing a careful laboratory study of rodent nutrition. You find that on days when the lab is quiet, the rats in the lab consume on average 4 slices of pizza per day, with a standard deviation of 1 slice. However, on days when your annoying fun-loving labmate shows up and insists on playing loud rock music, the rats consume the same average number of pizza slices but with a standard deviation of 2 slices. On days when your labmate is present, what proportion of the VARIANCE in the rats' pizza consumption do you conclude is due to rock music specifically? Express your answer to the nearest 0.01