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Version 7.0 (R2008b) Statistics Toolbox Software

This table summarizes what's new in Version 7.0 (R2008b):

New Features and Changes	Version Compatibility Considerations	Fixed Bugs and Known Problems	Related Documentation at Web Site
Yes Details below	Yes Summary	No	No

New features and changes introduced in this version are organized by these topics:

• Classification

• Data Organization

• Model Assessment

• Multivariate Methods

• Probability Distributions

• Regression Analysis

• Statistical Visualization

• Utility Functions

Classification

The new confusionmat function tabulates misclassifications by comparing known and predicted classes of observations.

Data Organization

Dataset arrays constructed by the dataset function can now be written to an external text file using the new export function.

When reading external text files into a dataset array, dataset has a new 'TreatAsEmpty' parameter for specifying strings to be treated as empty.

Compatibility Considerations

In previous versions, dataset used eval to evaluate strings in external text files before writing them into a dataset array. As a result, strings such as '1/1/2008' were treated as numerical expressions with two divides. Now, dataset treats such expressions as strings, and writes a string variable into the dataset array whenever a column in the external file contains a string that does not represent a valid scalar value.

Model Assessment

The cross-validation function, crossval, has new options for directly specifying loss functions for mean-squared error or misclassification rate, without having to provide a separate function M-file.

Multivariate Methods

The procrustes function has new options for computing linear transformations without scale or reflection components.

Probability Distributions

The multivariate normal functions mvnpdf, mvncdf, and mvnrnd now accept vector specification of diagonal covariance matrices, with corresponding gains in computational efficiency.

The hypergeometric distribution has been added to both the disttool and randtool graphical user interfaces.

Compatibility Considerations

The ksdensity function may give different answers for the case where there are censoring times beyond the last observed value. In this case, ksdensity tries to reduce the bias in its density estimate by folding kernel functions across a folding point so that they do not extend into the area that is completely censored. Two things have changed for this release:

1. In previous releases the folding point was the last observed value. In this release it is the first censoring time after the last observed value.

2. The folding procedure is applied not just when the 'function' parameter is 'pdf', but for all 'function' values.

Regression Analysis

The new nlmefit function fits nonlinear mixed-effects models to data with both fixed and random sources of variation. Mixed-effects models are commonly used with data over multiple groups, where measurements are correlated within groups but independent between groups.

Statistical Visualization

The boxplot function has new options for handling multiple grouping variables and extreme outliers.

The lsline, gline, refline, and refcurve functions now work with scatter plots produced by the scatter function. In previous versions, these functions worked only with scatter plots produced by the plot function.

The following visualization functions now have custom data cursors, displaying information such as observation numbers, group numbers, and the values of related variables:

• andrewsplot

• biplot

• ecdf

• glyphplot

• gplotmatrix

• gscatter

• normplot

• parallelcoords

• probplot

• qqplot

• scatterhist

• wblplot

Compatibility Considerations

Changes to boxplot have altered a number of default behaviors:

• Box labels are now drawn as text objects rather than tick labels. Any code that customizes the box labels by changing tick marks should now set the tick locations as well as the tick labels.

• The function no longer returns a handles array with a fixed number handles, and the order and meaning of the handles now depends on which options are selected. To locate a handle of interest, search for its 'Tag' property using findobj. 'Tag' values for box plot components are listed on the boxplot reference page.

• There are now valid handles for outliers, even when boxes have no outliers. In previous releases, the handles array returned by the function had NaN values in place of handles when boxes had no outliers. Now the 'xdata' and 'ydata' for outliers are NaN when there are no outliers.

• For small groups, the 'notch' parameter sometimes produces notches that extend outside of the box. In previous releases, the notch was truncated to the extent of the box, which could produce a misleading display. A new value of 'markers' for this parameter avoids the display issue.

As a consequence, the anova1 function, which displays notched box plots for grouped data, may show notches that extend outside the boxes.

Utility Functions

The statistics options structure created by statset now includes a Jacobian field to specify whether or not an objective function can return the Jacobian as a second output.

Version 7.1 (R2009a) Statistics Toolbox Software

Version 6.2 (R2008a) Statistics Toolbox Software

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