Gribbles are small, pale white, Marine worms that bore through wood. While sometime considered a pest since they can wreck wooden docks and piers, they are now being studied to determine whether the enzyme they secrete will allow us to turn inedible wood and plant waste into biofuel. Suppose that the length of a gribble is Normallyr distributed with an average length of 3.1 mm and a standard deviation of 0.52 mm