3. Production Process Characterization
3.5. Case Studies
3.5.2. Machine Screw Case Study

## Work This Example Yourself

View Dataplot Macro for this Case Study This page allows you to repeat the analysis outlined in the case study description on the previous page using Dataplot, if you have downloaded and installed it. Output from each analysis step below will be displayed in one or more of the Dataplot windows. The four main windows are the Output window, the Graphics window, the Command History window and the Data Sheet window. Across the top of the main windows there are menus for executing Dataplot commands. Across the bottom is a command entry window where commands can be typed in.
Data Analysis Steps Results and Conclusions

Click on the links below to start Dataplot and run this case study yourself. Each step may use results from previous steps, so please be patient. Wait until the software verifies that the current step is complete before clicking on the next step.

The links in this column will connect you with more detailed information about each analysis step from the case study description.

```1. Get set up and started.
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```   1. Read in the data.

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``` 1. You have read 5 columns of numbers
into Dataplot, variables machine,
day, time, sample, and diameter.
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```2. Box Plots by Factor Variables
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```   1. Generate a box plot by machine.

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```   2. Generate a box plot by day.

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```   3. Generate a box plot by time of
day.

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```   4. Generate a box plot by
sample.

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``` 1. The box plot shows significant
variation for both location and
spread.

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``` 2. The box plot shows no significant
location or spread effects for
day.

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``` 3. The box plot shows no significant
location or spread effects for
time of day.

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``` 4. The box plot shows no significant
location or spread effects for
sample.

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```3. Analysis of Variance
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```   1. Perform an analysis of variance
with all factors.

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```   2. Perform an analysis of variance
with only the machine factor.

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```   3. Perform model validation by
generating a 4-plot of the
residuals.

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``` 1. The analysis of variance shows
that only the machine factor
is statistically significant.

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``` 2. The analysis of variance shows
the overall mean and the
effect estimates for the levels
of the machine variable.

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``` 3. The 4-plot of the residuals does
not indicate any significant
problems with the model.

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```4. Graph of Throughput
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```   1. Generate a graph of the
throughput.

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```   2. Perform an analysis of
variance of the throughput.

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``` 1. The graph shows the throughput
for machine 3 is lower than
the other machines.

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``` 2. The effect estimates from the
ANIVA are given.

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