You manufacture car batteries and need to determine how long you will provide a warranty under which you will replace a battery for free if it fails before the warranty runs out. You know from testing that a battery's life span is normally distributed and has a mean of 4.3 years with a standard deviation of 0.92. You want to ensure that you replace a maximum of 33% of batteries for free. For how long will you make the limited warranty on the batteries last? Why? What role does customer satisfaction play in making this decision?