Power Calculation, Several Means, Planned Contrast

Power calculation for planned contrast with option for charts of power vs. sample size, power vs. standardized effect size and, power vs. alpha level

General

Element Name Description
Group Sample Size The number of samples in each group, assuming all group sizes are equal (acceptable range 2 to 150000).
Number of Groups Number of groups in the analysis (acceptable range 2 to 200).
Standardized Effect Standardized effect for use in the model (acceptable range -5000 to 5000).
Alpha Level Alpha level (Type I error rate used in determining the critical value of the t-statistic) (acceptable range 0.0001 to 0.25).
SS Weights Sum of the squares of the contrast weights used in computing the contrast being tested.
Detail of computed results reported Output level of detail selection:

 Power Calculation produces Power Calculation Spreadsheet;

 Pwr Calc plus Charts option produces, in addition, Power vs. Sample Size chart, Power vs. Standardized Effect, and Power vs. Alpha Level charts.

Chart Parameters

Element Name Description
Number of Steps. (For charts only) Number of individual steps for which to calculate power between the starting and ending parameter values for Power Charts (Min 4, Max 100).
Starting Sample Size. (For charts only) Initial sample size for calculation of Power vs. Sample Size chart (acceptable range 2 to 140,000).
Ending Sample Size. (For charts only) Final sample size for calculation of Power vs. Sample Size chart (acceptable range 5 to 150,000).
Starting Standardized Effect. (For charts only) Initial standardized effect size for calculation of Power vs. Standardized Effect chart (acceptable range 0.01 to 9).
Ending Standardized Effect. (For charts only) Final standardized effect size for calculation of Power vs. Standardized Effect chart (acceptable range 0.02 to 10).
Starting Alpha Level. (For charts only) Initial alpha level for calculation of Power vs. Alpha Level chart (acceptable range 0.0001 to 0.2499).
Ending Alpha Level. (For charts only) Final alpha level for calculation of Power vs. Alpha Level chart (acceptable range 0.0002 to 0.25).