A sudden change in a particular production process has lowered the process mean by 1 standard deviation. It has been determined that the weight of the product being measured is approximately normally distributed. Furthermore, it is known that the recent change had virtually no effect on the variability of this process. What proportion of points is expected to fall outside the control limits on the X̅ chart if the subsample size is 4? Compute this proportion again for the case where the subsample size is 9. Provide an explanation for the difference between these two proportions.