Ground Coffee Empties into a Chute Containing a Roll of Plastic,which

Ground coffee empties into a chute containing a roll of plastic,which forms a sealed bag of coffee.The weight on the coffee bag states the weight is 6 ounces.From every ten bags filled,four are randomly sampled and weighed to see if the mean is correct (the process in control).The standard deviation of the filling process is 0.05 ounces.Compute the 3-sigma lower control limit for the mean chart.