Question 1 Six samples of five observations each have been taken of 80kg concrete slabs produced by a machine and the results is showed below. a) Please choose the suitable control charts to test whether or not the process is in control. b) Based on the data in part a), the specification for the concrete slabs is 78kg to 81kg, is the specification being met, calculate both cp and cpk ? Using the formulation = 3nA2R ( n is sample size and A2 refers to tables in Week 8 slide) to estimate the standard deviation from average range