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.
1. Read in the data.

1. You have read 4 columns of numbers
into Dataplot: variables Y, X1, X2,
and X3.

2. Plot the main effects.
1. Ordered data plot.
2. DOE scatter plot.
3. DOE mean plot.

1. Ordered data plot shows factor 1
clearly important, factor 2
somewhat important.
2. DOE scatter plot shows significant
differences for factors 1 and 2.
3. DOE mean plot shows significant
differences in means for factors
1 and 2.

3. Plots for interaction effects
1. Generate a DOE interaction
effects matrix plot.

1. The DOE interaction effects matrix
plot does not show any major
interaction effects.

4. Block plots for main and interaction effects
1. Generate block plots.

1. The block plots show that the
factor 1 and factor 2 effects
are consistent over all
combinations of the other
factors.

5. Estimate main and interaction effects
1. Perform a Yates fit to estimate the
main effects and interaction effects.

1. The Yates analysis shows that the
factor 1 and factor 2 main effects
are significant, and the interaction
for factors 2 and 3 is at the
boundary of statistical significance.

6. Model selection
1. Generate halfnormal
probability plots of the effects.
2. Generate a Youden plot of the
effects.

1. The probability plot indicates
that the model should include
main effects for factors 1 and 2.
2. The Youden plot indicates
that the model should include
main effects for factors 1 and 2.

7. Model validation
1. Compute residuals and predicted values
from the partial model suggested by
the Yates analysis.
2. Generate residual plots to validate
the model.

1. Check the link for the
values of the residual and
predicted values.
2. The residual plots do not
indicate any major problems
with the model using main
effects for factors 1 and 2.

8. DOE contour plot
1. Generate a DOE contour plot using
factors 1 and 2.

1. The DOE contour plot shows
X1 = 1 and X2 = +1 to be the
best settings.
