The maintenance and parks department for a small city in Michigan has the responsibility of watering the potted plants that hang from the city's light posts. Because of the harsh winter weather, the plants are only living from the beginning of May to the end of September. The city has a water truck that can carry enough to water all the plants in the city. The truck is equipped with a hose and nozzle. One employee drives the truck and one employee operates the hose. Up until now, the city had no standard for the amount of time this job should take. On some days, the two employees might be gone four hours and on other days up to six hours. As the new cost accountant for the city, you have asked to set the direct labor quantity standard. 

How would you go about determining this standard?