A carpenter is making doors that are 2058 millimeters tall. if the doors are too long they must be trimmed, and if they are too short they cannot be used. a sample of 21 doors is taken, and it is found that they have a mean of 2069 millimeters with a standard deviation of 18 . assume the population is normally distributed. is there evidence at the 0.05 level that the doors are too long and need to be trimmed?