# Sample Planning Wizard: Description

Whether you are a novice researcher or a world-class statistician, the Sample Planning Wizard can help you identify the right sampling plan for your research.

## What the Wizard Does

The Sample Planning Wizard allows you to easily assess how different design decisions (sample size, sampling method, etc.) affect the precision and cost of your research. For example, you can quickly find the design that:

• Requires the smallest sample size to achieve a specified sampling error.
• Delivers the smallest sampling error, given a fixed sample size.
• Delivers the smallest sampling error, given a fixed budget.
• Achieves a specified sampling error for the smallest cost.

If you are conducting a hypotheis test, the Wizard can assess the statistical power associated with your design.

• You specify effect size (the amount of error you can tolerate), and the Wizard calculates the power of your test.
• Or you specify power, and the Wizard calculates effect size.

And the Wizard even works with small samples.

• With mean scores, the Wizard uses the t-distribution to compute statistical properties (e.g., confidence intervals, standard errors, etc.) when the sample size is less than 30.
• With proportions, the Wizard uses a binomial distribution for small samples when sampling with replacement; and a hypergeometric distribution when sampling without replacement.

## How the Wizard Works

The Sample Planning Wizard makes it easy to create powerful, cost-effective sampling plans.

• Use simple point-and-click inputs to describe the analysis you want to conduct.
• Based on your research goals, the Wizard prompts you for any additional data needed to evaluate your sampling plan.
• A final report, written in plain English, appears in seconds. The report documents key elements of your plan (sampling method, sample size, cost of implementation, etc.), describes statistical properties (margin of error, confidence interval, power of statistical tests, etc.) associated with your plan, and offers suggestions for improvement.

The Wizard defines terms and provides user-friendly Help screens at each stage of the analysis.

## How to Access the Wizard

The Sample Planning Wizard is available only to registered users. Before you register, though, you may want to play with a demo version of the Wizard. The demo is free, and it will allow you to quickly determine whether the Wizard is right for you.

If you like the demo, register to use the full Wizard. A one-month license costs \$10. And satisfaction is guaranteed. If you are dissatisfied, just contact us within 30 days; and we will issue a full refund.

Once you have registered, you can access the Wizard from the Stat Tools tab, which appears in the header of every Stat Trek web page. Just click the Wizard link under the tab. Or you can click the button below.