A process that is considered to be in control measures an ingredient in ounces. Below are the last 10 samples (each size ) taken.

				SAMPLES
1	2	3	4	5	6	7	8	9	10
10	9	13	10	12	10	10	13	8	10
9	9	9	10	10	10	11	10	8	12
10	11	10	11	9	8	10	8	12	9
9	11	10	10	11	12	8	10	12	8
12	10	9	10	10	9	9	8	9	12

a) What is the process standard deviation? What is

b) If , what are the control limits for the mean chart

c) What are the control limits for the range chart?

d) Is the process in control?