Analyse-It
Statistical software integrated into Microsoft Excel for linear regression, anova, chi-square and other functions. Download evaluation.

XLSTAT
Data analysis and statistics add-in for Excel. Includes over 40 statistical and data analysis features for statistics experts, researchers, students, and teachers. Buy on-line or download trial version.

SigmaXL
Pareto Pro is an add-in for Microsoft Excel 97, 2000 and XP, which allows you to create single and multiple charts. Performs analysis that will slice and dice data. Includes free demos and product list.

WinSTAT
An Excel Add-In providing statistical tests and diagrams. Demonstration download.

statistiXL
Statistics add-in for Microsoft Excel. Includes univariate and multivariate tests such as ANOVA, Correlation, Regression, PCA, Factor and Discriminant Analysis.