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Z:\Manual\DX9\DX9-FT1-Simple Sample.docx7/31/2013 9:14:00 AM
Design-Expert® software version 9: Simple Sample Design
Version 9 of Design-Expert (DX9) features a “simple sample design” that facilitates a straight-forward
analysis of raw data, making it easy to calculate the mean
and other statistics that characterize measurements.
To illustrate the simple sample tools of DX9, let’s
characterize the performance of a motor-shaft supplier.
The data, shown below, is a measure of the endplay:
61, 61, 57, 56, 60, 52, 62, 59, 62, 67, 55, 56, 52, 60, 59, 59,
60, 59, 49, 42, 55, 67, 53, 66, 60. The purchaser needs the
mean, standard deviation, and 95% confidence interval of
this vital attribute.
Off the Factorial tab select Simple Sample and, as shown in
the screen shot, enter the Response Name “Endplay” and
Rows 25 for the number of observations. Then click
Continue. The program then presents a blank data entry
sheet—a “design layout.”
Either type in the data now or open the file “Simple Sample-Motor Shaft.dxpx” that has it pre-entered.
Now proceed with
the analysis by going
to the R1: Endplay
node and pressing
forward to the
ANOVA tab. DesignExpert then presents
the needed statistics
as seen here.
Check out the graphs
under Diagnostics
(run 20 bears
watching as you will see by changing to the Externally Studentized scale for the Resid vs Run chart) as
well as the 95%-confidencebanded model graph copied out to
Simple Sample
the right. Also, take a look at the
tool under the Post Analysis node
for Point Prediction, in particular
the tolerance interval, a very
useful statistic for a purchaser who
needs to establish incoming
specifications.
Design-Expert® Software
Endplay
Design Points
95% CI Bands
70
Std # 20 Run # 20
Y = Endplay = 42
CI = (55.6418, 60.2782)
65
E n d p la y
60
55
50
45
This concludes our feature tour of
simple sample tools in DX9. Feel
free to explore other tools. If you
need more information at any
time, press for Tips, Screen Tips off
the main menu or push the light bulb icon.
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