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Glossary

Active Data Set
Q-Q-Plot
Acknowledgement
Disclaimer


Active Data Set

All estimation and visualization procedures use the active data set. This is the data set most recently loaded (see Load Data) or generated by a simulation. One may activate another data set by means of the Choose Data option that lists all data sets used during a session.

Q-Q-Plot

Let F[mu,sigma] be dfs with location and scale parameters mu and sigma. The sample q-quantile is plotted against the q-quantile of the standard df F = F[0,1].
If the data are governed by F[mu,sigma], then the Q-Q-plot is close to a line with slope sigma and intercept mu (see Statistical Analysis, page 56, for details). A stronger deviation from a straight line indicates that the modeling by the location- and scale-parameter family is not adequate. An additional shape parameter must first be replaced by an estimate.
More precisely, the ith ordered value x[i:n] is plotted against the standard quantile function (qf) evaluated at q(i) = (i-1/3)/(n+1/3). In addition, there is a linear interpolation of the points (if this is the actual plotting option).

Acknowledgement

We refer to the Preface of Statistical Analysis for the names of those who assisted in programming Xtremes 3.1.

Disclaimer

Xtremes Group does not offer any representations or warranties for Xtremes Group products in respect to their performance or fitness for a particular purpose. Xtremes Group believes that the information contained in this manual is correct. However, Xtremes Group reserves the right to revise the product hereof and make any changes to the contents without the obligation to notify any user of this revision. Xtremes Group does not assume the responsibility for the use of this manual, nor the product described therein.

© 2005
Xtremes Group · updated Jun 21, 2005