A study measured how long men and women stared at the new 146" HD HGTV. Of the 97 men, the average was 21.2 minutes with a standard deviation of 2.3 minutes. Of the 25 women, the average was 10.4 minutes with a standard deviation of 5.8 minutes. The average difference was 10.8 minutes, and the standard deviation of the differences was 0.76. Find a 87% confidence interval for the average difference between the two genders.