A manufacturer of salad dressings uses machines to dispense liquid

A manufacturer of salad dressings uses machines to dispense liquid ingredients into bottles that move along a filling line. The machine that dispenses dressings is working properly when the mean amount dispensed is 330ml. The population standard deviation of the amount dispensed is 4ml. A sample of 50 bottles is selected periodically, and the filling line is stopped if there is evidence that the mean amount dispensed is different from 330ml. Suppose that the mean amount dispensed in a particular sample of 50 bottles is 329.7ml. Is there evidence that the population mean amount is different from 330ml?(use a 0.05 level of significance)