Need help with this one as well

The control limits of x-bar and R charts for a certain component with a subgroup size of four is given as 2.05+0.02. It is also given that for 20 subgroups the value of sigma x and sigma R are 41.288 and 0.280 respectively. If the dimensions fall above USL , the rework is required . If falls below LSL the component must be scrapped. If the process is in a state of statical control and normally distributed them. (a) Calculate 3- sigma limits

(b) Find the process capability

(c) Determine percentage of rework and scrap

(d) If the process is centered exactly to specification of mean, what fraction of the

non confirmed is being produced ?