An automotive parts supplier assesses the usability and qualityof the door locks that they provide. The locks are manufactured atthree different plants. The production manager wants to determinewhether the plant affects the final product. The production managercollects data on locks from each plant, and gives a usability andquality rating. Data are found in the file Car LockRatings.
a) State the null and alternate hypothesis we would run todetermine if the Usability rating across all threemanufacturing plants is the same.
b) Run a one-way ANOVA on these data. Show output.
c) What conclusions can you make based on the p-value of thistest?
d) Obtain boxplot, residuals scatter plot, and individualresidual Normal probability plots.
e) Have all assumptions been met? Explain using your plots toillustrate your answer.
| Usibility Rating | |
| Plant A | Plant B | Plant C |
| 5 | 6 | 5 |
| 6 | 4 | 4 |
| 5 | 5 | 6 |
| 6 | 4 | 6 |
| 6 | 3 | 5 |
| 5 | 4 | 7 |
| 4 | 5 | 6 |
| 3 | 5 | 5 |
| 4 | 6 | 4 |
| 5 | 5 | 4 |
| 4 | 5 | 4 |
| 3 | 6 | 5 |
| 6 | 7 | 5 |
| 7 | 7 | 6 |
| 8 | 6 | 5 |
| 6 | 7 | 6 |
| 8 | 6 | 6 |
| 7 | | 5 |
| 6 | | 6 |
| 5 | | 7 |
| 6 | | 5 |
| 7 | | |
| 7 | | |
| 8 | | |
