Select the Quick tab of the
Planned
Contrast: Power Calculation Parameters dialog box to access options
to establish the basic parameters for analyzing power for the planned
contrast.

Fixed Parameters. The entries in the boxes under Fixed Parameters establish the values for the fixed parameters in the power calculation.

N per Group. In the N per Group box, enter the sample size per group.

No. of Groups. In the No. of Groups box, enter the number of independent samples on which the analysis is based. This should be the total number of independent samples available that are assumed to have equal standard deviations.

Es. In the Es box, enter the standardized effect. Note that you can click the Calculate Es button to have STATISTICA calculate it from cell means and contrast weights.

Alpha. In the Alpha box, enter the type I error rate used in determining the critical value for the t-statistic.

SS Weights. In the SS Weights box, enter the sum of the squares of the contrast weights used in computing the contrast being tested. Note that you can click the Calculate Es button to have STATISTICA calculate it.

Calculate Es. Click the Calculate Es button to display the Planned Contrast: Effects Calculation dialog box. Use this dialog box to have STATISTICA calculate the sum of squares of the contrasts weights (needed for the sample size calculation) as well as the standardized effect (Es).