GPS-X Technical Reference

385 Optimizer
Level of significance for lack of fit test: This is the level of significance used in the lack
of fit test. An appropriate message is printed by GPS-X depending on the calculated
probability value and the level of significance. If the probability for a certain target
variable is smaller than the chosen significance level, it indicates that there is a lack of fit
associated with this target variable.
Replication sum of squares ( User Supplied / Calculated ): This option allows the user
to specify whether the replication sums of squares used in the lack of fit test are user
supplied or calculated by GPS-X using repeat measurements.
Relative tolerance used to detect repeat measurements: This is the relative difference
used when detecting repeat measurements in the data set. The default value is 1.0E-4.
Repeat measurements are inserted into GPS-X by placing measurements very close
together in time in the .dat file. GPS-X identifies repeat measurements by checking the
relative difference between all of the times entered into the .dat file. If the relative
difference between two time values is less than the replication tolerance, the
corresponding measurements are considered to be repeats for the purposes of calculating
the lack of fit test.
User-Supplied Replication Sum of Squares Sub-Section
This sub-section is accessed by clicking on the More... button in the Lack of Fit
sub-section.
Number of target variables: This is the number of target variables used in the
optimization. It is only used to size the replication sum of squares array and the degrees
of freedom for replication sum of squares array.
Replication sum of squares: This is an array for entering a replication sum of squares
for each target variable. This is useful if you do not have repeat measurements but you
have a good estimate of the measurement variance from past experience.
Degrees of freedom for replication sum of squares: This is an array for entering the
degrees of freedom associated with each user supplied replication sum of squares. If you
do not have this information you can enter rough estimates. Keep in mind that a large
degrees of freedom value implies a high degree of confidence in the variance estimate.
GPS-X Technical Reference