The following table contains information on matched sample values whose differences are normally distributed. (You may find it useful to reference the appropriate table: z table or t table) Number Sample 1 Sample 2 18 21 12 11 21 23 22 20 ONOURWNH 16 20 14 17 17 17 18 22 Let the difference be defined as Sample 1 - Sample 2. a. Construct the 95% confidence interval for the mean difference up. (Negative values should be indicated by a minus sign. Round intermediate calculations to at least 4 decimal places and final answers to 2 decimal places.) Confidence interval is to