The accompanying data file contains information on matched sample observations whose differences are normally distributed. (You may find it useful to reference the appropriate table: ztable or table) pictureClick here for the Excel Data File Let the difference be defined as Sample 1-Sample 2. a. Construct the 99% confidence interval for the mean difference up (Negative value should be indicated by a mínus sign. Round final answers to 2 decimal places.) Confidence interval is to 1 Sample 1 Sample_ 17 12 S 6 8 20 23 16 14 19 2 2 2 1 1