A toy-manufacturing company has been given a large order for small plastic whistles that will be given away by a large fast-food hamburger chain with its kids’ meal. Seven random samples of four whistles have been taken. The mass of each whistle has been ascertained in grams. The data are shown here. Use these data to construct an x̄-chart and an R chart. What managerial decisions should be made on the basis of these findings?