PASS 2008
功效分析和样本大小 - 市面上最好的功效分析软件

Power Analysis

A statistical test's power is the probability that the test procedure will result in statistical significance. Power is related to the sample size, the size of the type I (alpha) error, the actual size of the effect, and the size of experimental error. All of these must be considered in order to calculate statistical power.

As statistical significance is usually the desired outcome, planning and running a study to achieve a high power is of prime importance to the researcher. Because of the complexity of the calculations, the determination of the power is often ignored or only a casual attempt is made at its calculation by adopting some, so-called, "rule-of-thumb."

PASS Beats the Competition!

PASS performs power analysis and calculates sample sizes. Use it before you begin a study to calculate an appropriate sample size (it meets the requirements of government agencies that demand technical justification of the sample size you have used). Use it after a study to determine if your sample size was large enough.

PASS lets you solve for power, sample size, effect size, and alpha level. It automatically displays charts and graphs along with numeric tables and text summaries in a portable format that is cut and paste compatible with all word processors so you can easily include the results in your proposal.

PASS is a standalone system. Although it is integrated with NCSS, you do not have to own NCSS to run it. You can use it with any statistical software you want. PASS 2008 runs under Windows Vista, XP, 2000, NT, ME, 98, and 95.

PASS is accurate. It has been extensively verified using books and reference articles. Proof of the accuracy of each procedure is included in the extensive documentation.

PASS comes with three manuals that contain tutorials, examples, annotated output, references, formulas, verification, and complete instructions on each procedure. And, if you cannot find an answer in the manual, our free technical support staff (which includes three PhD statisticians) is available.

No other program calculates sample sizes and power for as many different statistical procedures as does PASS. Specifying your input is easy, especially with the online help and manual.

Choose PASS. It's more comprehensive, easier-to-use, accurate, and less expensive than any other sample size program on the market.

Features. PASS is the most comprehensive sample size program available with over 150 statistical procedures. Accuracy of each procedures is well validated. PASS is easy to learn and use. PASS is a standalone software package (no other stat package is required). PASS easily produces sharp, flexible graphics. PASS output is easily transferred to popular word processors and presentation software such as PowerPoint.

7-Day Trial. Go ahead, download a 7-day trial version of PASS today. During the trial period, the spreadsheet is limited to 100 rows of data. You can try all of the statistical procedures, import/export your data, and print your reports. This is an excellent way to become acquainted with PASS.