spc: Statistical Process Control – Collection of Some Useful Functions. Evaluation of control charts by means of the zero-state, steady-state ARL (Average Run Length) and RL quantiles. Setting up control charts for given in-control ARL. The control charts under consideration are one- and two-sided EWMA, CUSUM, and Shiryaev-Roberts schemes for monitoring the mean of normally distributed independent data. ARL calculation of the same set of schemes under drift are added. Other charts and parameters are in preparation. Further SPC areas will be covered as well (sampling plans, capability indices ...).