Jack invites some neighbors to his Thanksgiving party. He wants them to feel comfortable, so notices how long they choose to stay at the party. Assume the time is normally distributed. Of the 20 men they stayed an average of 50 minutes with a standard deviation of 18 minutes. Of the 20 women they stayed an average of 20 minutes with a standard deviation of 5 minutes. The difference in the averages was 30 minutes. The standard deviation of difference between the men and women was 0.4 minutes. Find a 90% confidence interval for the difference in the average time for men and women who attend Mr. Ripper's party.