A light bulb manufacturer wants to estimate the total number of defective bulbs contained in all of the boxes shipped by the company during the past week. Production personnel at this company have recorded the number of defective bulbs found in each of 50 randomly selected boxes shipped during the past week. These data are provided in the file P08_12.xlsx. Find a 95% confidence interval for the total number of defective bulbs contained in the 1000 boxes shipped by this company during the past week.