1. Auto pistons at Kevins plant in Pueblo are produced in a forging process, and the diameter is a critical factor that must be controlled. From sample size of 6 pistons produced each day, the mean and the range of this diameter have been as follows:

Day	Mean (MM)	Range (MM)
1	66.9	4.2
2	63.2	4.6
3	63.6	4.1
4	65.5	4.0
5	66.6	4.5

*round your answers to three decimal places.

1) What is the value of X-double bar (mean of sample means)? _65.16________________

2) What is the value of (average range)? ______4.28____________

3) What are the UCL and LCL of X-bar chart? UCL:___________, LCL: _____________

4) What are the UCL and LCL of R chart? UCL: ___________, LCL: _____________

( can someone please double check 1 and 2 for me. Also can someone explain how they are getting the answer for 3 and 4 please).