mathematics

PS Power and Sample Size

PS Power and Sample Size is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand PS Power and Sample Size rather than just read about it. In short: PS is an interactive computer program for performing statistical power and sample size calculations. Program description The P program can be used for studies with dichotomous, continuous, or survival response measures.

Key takeaways

PS Power and Sample Size belongs to mathematics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PS Power and Sample Size to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PS Power and Sample Size from memory before moving on to harder problems.

Reference excerpt

PS is an interactive computer program for performing statistical power and sample size calculations.

Program description The P program can be used for studies with dichotomous, continuous, or survival response measures. The user specifies the alternative hypothesis in terms of differing response rates, means, survival times, relative risks, or odds ratios. Matched or independent study designs may be used. Power, sample size, and the detectable alternative hypothesis are interrelated. The user specifies any two of these three quantities and the program derives the third. A description of each calculation, written in English, is generated and may be copied into the user's documents. Interactive help is available. The program provides methods that are appropriate for matched and independent t-tests, survival analysis, matched and unmatched studies of dichotomous events, the Mantel-Haenszel test, and linear regression. The program can generate graphs of the relationships between power, sample size and the detectable alternative hypothesis. It can plot graphs of any two of these variables while holding the third constant. Linear or logarithmic axes may be used and multiple curves can be plotted on each graph. Graphs may be copied and pasted into other documents or programs for further editing.

Reviews Reviews of this program have been published by McCrum-Gardner, Thomas and Krebs, Stawicki and Pezzullo.

Web version A web-based version of the program is also available at https://cqsclinical.app.vumc.org/ps/.

References

External links PS Webpage P3G : Public Population Project in Genomics and Society CTSpedia UCSF Biostatistics Software Informer

Illustrations

Worked examples

Example 1 — a first encounter with PS Power and Sample Size

Start with the simplest possible case. Write down what PS Power and Sample Size claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to PS Power and Sample Size before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about PS Power and Sample Size ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of PS Power and Sample Size

In research: PS Power and Sample Size appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses PS Power and Sample Size in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: PS Power and Sample Size is common in secondary-school and first-year university syllabi. It links to neighbouring topics Statistical software, so understanding it makes those chapters shorter.
In everyday life: Look for PS Power and Sample Size outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study PS Power and Sample Size in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PS Power and Sample Size means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain PS Power and Sample Size out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PS Power and Sample Size in simple terms?

PS is an interactive computer program for performing statistical power and sample size calculations. Program description The P program can be used for studies with dichotomous, continuous, or survival response measures.

Why does PS Power and Sample Size matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study PS Power and Sample Size?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on PS Power and Sample Size.