Control charts on X and S are to be maintained on the torque reading of a bearing used in a wingflap actuator assembly. Samples of size n-8 are to be used, and we know from past experience that when the process is in control, bearing torque has a normal distribution with mean μ-: 80 inch-pounds and standard deviation σ center line and control limits for these control charts -12 inch-pounds. Find the center line and control limits for these control charts.