Question

A company is concerned about the quality of production in its four plants. To test the quality, managers take measurements of valve openings (the dependent variable) by one machine operator (the independent variable) in each plant. The results are stacked in columns by operator 1 through 4 below.

6.33       6.26     6.44    6.29

6.26       6.36     6.38    6.23

6.31       6.23     6.58    6.19

6.29       6.27     6.54    6.21

6.4         6.19     6.56

               6.5       6.34

               6.19     6.58

               6.22

Please provide the five step hypothesis testing process using a 5% level of significance, conduct a post-hoc test if required, and provide the Minitab output for the ANOVA and post-hoc test.

To conduct this test in Minitab, please use the following process:

Stack the data in columns as given above. To begin a one-way ANOVA with Stacked Data, select Stat from the menu bar. Select ANOVA from the pulldown menu. Select One-Way. In the slot Response, list the column containing the observations. In the slot Factor, list the column containing the group identifiers. For multiple comparisons, select Comparisons and make your selection from the dialog box that appears. The multiple comparison options are Tukey’s, Fisher’s, Dunnett’s, or Hsu’s MCB tests. In the multiple comparison dialog box, you can insert the family error rate in the box on the right as a whole number.

Answer 1