Select the Quick tab of the Log-Rank Test: Power Calculation Results dialog box to access options to interactively view the results of power calculations and generate plots of power as a function of quantities that affect power 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 Power Charts.

Start N. In the Start
N box, enter the starting value of N to use in the Power vs. N

End N. In the End
N box, enter the final value of N to use in the Power vs. N

Start Pi2. In the Start Pi2 box, enter the starting value of Pi2 used in the Power vs. Pi2 power chart.

End Pi2. In the End Pi2 box, enter the final value of Pi2 used in the Power vs. Pi2 power chart.

Start Alpha. In the Start Alpha box, enter the starting value of Alpha to use in the Power vs. Alpha power chart.

End Alpha. In the End
Alpha box, enter the final value of Alpha to use in the Power vs.
Alpha

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

Power Charts. Click the buttons under Power Charts to produce charts of power as a function of variables known to affect it. Note that parameters given under X-Axis Graphing Parameters control the range of values plotted on the X-axis and the number of steps plotted.

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

Power vs. Pi2. Click the Power vs. Pi2 button to produce a plot of power vs. Pi2.

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