Auto pistons at Wemming Chung's plant in Shanghai are produced in a forging process, and the diameter is a critical factor that must be controlled. From sample sizes of 10 pistons produced each day, the mean and the range of this diameter have been as follows: Day Mean Bold x overbar (mm) Range R (mm) 1 156.9 4.4 2 155.2 4.4 3 153.6 4.3 4 157.5 4.8 5 158.6 4.5 (a) What is the value of x double overbar?
