A new post-surgical treatment is being compared with a standard treatment. Seven subjects receive the new treatment, while seven others (the controls) receive the standard treatment. The recovery times, in days, are given below. Treatment: 12 13 15 19 20 21 22 Control: 18 23 24 30 32 35 39 Let X represent the population mean for the control patients and let Y represent the population mean for the treated patients. Find a 98% confidence interval for the difference XY . Round down the degrees of freedom to the nearest integer and round the answers to three decimal places. The 98% confidence interval is