Select the Quick tab of the Single Proportion: 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 Pi. In the Start Pi box, enter the starting value of Pi used in the Power vs. Pi power chart.

End Pi. In the End Pi box, enter the final value of Pi used in the Power vs. Pi 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.

Algorithm. The Power Analysis module allows you to choose from two algorithms:

Exact. Select the Exact option button to use the binomial distribution to calculate the exact probability of rejecting the null hypothesis, using the standard rejection points (obtained from a normal approximation) used in the test.

Approximate. Select the Approximate option button to use the normal approximation to the binomial distribution to calculate the approximate probability of rejecting the null hypothesis.

Power Charts. Click the buttons in the Power Charts group box to produce charts of power as a function of sample size, 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.

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

Power vs. Pi. Click the Power vs. Pi button to produce a plot of power versus Pi (the population proportion).

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