1. Quality In Manufacturing : US Minting and Nickel Weight
Kate Gilland
Team #15

2. Executive Summary
Concern that the nickel specifications are not being met during manufacturing
Research and collect data to be able to test this concern.
Conclude based on the data analyzed as well as the results generated by the various charts

3. Specifications Weight: 5.000 g Composition:
Cupro-Nickel: 25% Ni, Balance Cu
Weight:
5.000 g
Diameter:
0.835 in., mm
Thickness:
1.95 mm
Edge:
Plain

4. Data Collection
One nickel was sampled every 10 minutes throughout the course of an 8 hour work day.
The results of the weights of these nickels (in grams) is shown here.

5. Time Series Plot

6. Test for Normality
a probability plot was used to test for the first main assumption of normality. there seems to be a slight ‘S’ pattern , more towards the begininging of the data points. However, it still appears that the weight data for the nickels is normal, with a mean of and a standard deviation of

7. Test for Independence

8. Control Charts
The moving range control chart shows observation 10 as OOC, above the upper control limit.

9. Estimate of AR(1) model: Xt=4.58260+0.0851
Autocorrelation
Final Estimates of Parameters
Type Coef SE Coef T P AR
Constant
Mean
Number of observations: 48
Residuals: SS = (backforecasts excluded)
MS = DF = 46
Modified Box-Pierce (Ljung-Box) Chi-Square statistic
Lag
Chi-Square *
DF *
P-Value *
Estimate of AR(1) model:
Xt=
T-1

10. Probability Plot of Residuals

11. Control Charts of Residuals

12. Conclusion Only one OOC point
Further tests to identify if Minting manufacturing of nickels needs to be altered

13. Resources
gCoins/?action=CircNickel