Calculating Required Sample Size

Select the Quick
tab of the 2-Way
ANOVA: Sample Size Calculation Results dialog box to access options
to interactively view the results of sample size calculations and generate
plots of required sample size as a function of quantities that affect
sample size in practice.

X-Axis Graphing Parameters. The entries in the boxes under X-Axis Graphing Parameters establish the start value, end value, and number of steps on the X-axis for the graphs specified under Sample Size Charts.

Start Power. In the Start
Power box, enter the starting value of power goal used in the N
vs. Power

End Power. In the End
Power box, enter the final value of power goal used in the N vs.
Power

Start RMSSE. In the Start RMSSE box, enter the starting value of RMSSE used in the N vs. RMSSE sample size chart.

End RMSSE. In the End RMSSE box, enter the final value of RMSSE used in the N vs. RMSSE sample size chart.

Start Alpha. In the Start Alpha box, enter the starting value of a used in the N vs. Alpha sample size chart.

End Alpha. In the End Alpha box, enter the final value of a used in the N vs. Alpha sample size chart.

No. of Steps. In the No. of Steps box, enter the number of steps, or intervals, plotted on the X-axis in the power charts specified in the Sample Size Charts box.

Sample Size Charts. Use the buttons under Sample Size Charts to produce charts of required degrees of freedom (Df) as a function of power goal, standardized effect size, or type I error rate. The range of values plotted on the X-axis, and the number of steps plotted, are controlled by parameters in the X-Axis Graphing Parameters box. Clicking any of the buttons will automatically produce sample size charts for row, column, and interaction effects.

N vs. RMSSE. Click the N vs. RMSSE button to

N vs. Alpha. Click the N vs. Alpha button to produce a plot of sample size (N) vs. Type I error rate.

N vs. Power. Click the N vs. Power button to produce a plot of sample size (N) versus power goal.