Calculating Required Sample Size

Select the Quick
tab of the Structural Equation Modeling: 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 the power goal used in the N vs. Power sample size chart.

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

Start R. In the Start R box, enter the starting value of R (RMSEA) used in the N vs. R power chart.

End R. In the End R box, enter the final value of R (RMSEA) used in the N vs. R power chart.

Start Df. In the Start
Df box, enter the starting
value of degrees of freedom (Df) used in the N vs. Df

End Df. In the End Df box, enter the final value of degrees of freedom (Df) used in the N vs. Df chart.

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

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

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

Sample Size Charts. Use the buttons under Sample Size Charts to produce charts of required N as a function of power goal, standardized effect size, or type I error rate. Note that parameters given in the X-Axis Graphing Parameters group box control the range of values plotted on the X-axis and the number of steps plotted.

N vs. R. Click the N vs. R button to produce a plot of N vs. RMSEA.

N vs. Df.

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

N vs. Power. Click the N vs. Power button to produce a plot of N versus power goal.