Don't get tied up in knots trying to figure out complex formulas in Excel,
use statistXL and open up a world of power data analysis with this Excel add-in.
Input your data and then use the built in statistical tests provided by
Analysis of Variance (ANOVA)
Simple, Partial, Multiple and Canonical Correlation
Linear and Circular Descriptive Statistics
Classification and Grouping Discriminant Analysis
Goodness of Fit Tests such as Binomial, Circular, Normal and Poisson
Simple and Multiple Linear Regression
Nonparametric Tests such as Friedman, Kruskal-Wallis and Mann-Whitney
Principal Component Analysis (PCA)
Univariate and Multivariate t-Tests
Output is straight to Excel so you can
take the results and work with them in the familiar Excel environment.