Problem 13-9

Resistors for electronic circuits are manufactured on ahigh-speed automated machine. The machine is set up to produce alarge run of resistors of 1,000 ohms each. Use Exhibit 10.13.

To set up the machine and to create a control chart to be usedthroughout the run, 15 samples were taken with four resistors ineach sample. The complete list of samples and their measured valuesare as follows: Use three-sigma control limits.

SAMPLE NUMBER		READINGS (IN OHMS)
1		1010	991	985	986
2		995	996	1009	994
3		990	1003	1015	1008
4		1015	1020	1009	998
5		1013	1019	1005	993
6		994	1001	994	1005
7		989	992	982	1020
8		1001	986	996	996
9		1006	989	1005	1007
10		992	1007	1006	979
11		996	1006	997	989
12		1019	996	991	1011
13		981	991	989	1003
14		999	993	988	984
15		1013	1002	1005	992

a. Calculate the mean and range for the abovesamples. (Round "Mean" to 2 decimal places and "Range" tothe nearest whole number.)

b. Determine X=X= and R?R? . (Roundyour answers to 3 decimal places.)

c. Determine the UCL and LCL for a X?X? chart.(Round your answers to 3 decimal places.)

d. Determine the UCL and LCL forR-chart. (Leave no cells blank - be certain toenter "0" wherever required. Round your answers to 3 decimalplaces.)

e. What comment can you make about theprocess?

o The process is in statistical control.

o The process is out of statistical control.