Beechcraft, Inc. wants to estimate the average tim eit takes the Beechjet corporation jet to climb from sea level to 41,000 feet. From previous experience, company engineers believe that the standard deviation of climbing time is 3 minutes. The model is tested in 120 random trials, and it is found that the sample mean is 21 minutes. Give a 95% confidence interval for the average climbing time from sea level to 41,000 feet.