Power and sample-size planning
Plans a prospective study of one mean with known sigma and a normal model, or two independent proportions using Cohen's arcsine h.
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Plans a prospective study of one mean with known sigma and a normal model, or two independent proportions using Cohen's arcsine h. This is an explicit approximation, not t-test power with unknown sigma or an exact binomial design. You choose the effect size, alpha and allocation; the smallest whole n that meets the model's power is returned. Group 1 can have at most 10 million. There is no guarantee that the study is valid.
Model, grammar and limits
δ=|Δ|/σ; h=2arcsin√p₁−2arcsin√p₂; π=Φ(δ/SE−zα)+Φ(−δ/SE−zα)
Limits: 256000 raw data characters, 5000 source records and 50000 cells in total; decimals up to 48 characters; up to 20 groups or contributions and 50 columns. Limits for exact and bootstrap methods are stated with each tool. Parsing and resource checks run before the calculation, and the worker stops after 15 seconds. Editing, canceling or resetting discards pending results.
Check assumptions, ties and missing values before drawing conclusions. Results show 10 significant digits; CSV keeps the numeric values and units. Exact enumeration means exact counts, not exact displayed decimals. Numerical tail zeros, floors and unavailable intervals are labeled. Nothing here is a diagnosis, proof of causation or validity approval.
Your data stays in this browser. The calculation runs in a local worker, and CSV and backup files are local downloads you choose to make. Your data is not sent anywhere or saved silently, so keep your original data. Input data, formulas and filenames are never sent. Only with your optional consent, Refentra sends aggregate counts of actions and outcomes, without input content.
Use the chosen model
- Model, grammar and limits
Plans a prospective study of one mean with known sigma and a normal model, or two independent proportions using Cohen's arcsine h. This is an explicit approximation, not t-test power with unknown sigma or an exact binomial design. You choose the effect size, alpha and allocation; the smallest whole n that meets the model's power is returned. Group 1 can have at most 10 million. There is no guarantee that the study is valid.
- Calculate
δ=|Δ|/σ; h=2arcsin√p₁−2arcsin√p₂; π=Φ(δ/SE−zα)+Φ(−δ/SE−zα). Limits: 256000 raw data characters, 5000 source records and 50000 cells in total; decimals up to 48 characters; up to 20 groups or contributions and 50 columns. Limits for exact and bootstrap methods are stated with each tool. Parsing and resource checks run before the calculation, and the worker stops after 15 seconds. Editing, canceling or resetting discards pending results.
- Download CSV report
Check assumptions, ties and missing values before drawing conclusions. Results show 10 significant digits; CSV keeps the numeric values and units. Exact enumeration means exact counts, not exact displayed decimals. Numerical tail zeros, floors and unavailable intervals are labeled. Nothing here is a diagnosis, proof of causation or validity approval. Your data stays in this browser. The calculation runs in a local worker, and CSV and backup files are local downloads you choose to make. Your data is not sent anywhere or saved silently, so keep your original data. Input data, formulas and filenames are never sent. Only with your optional consent, Refentra sends aggregate counts of actions and outcomes, without input content.
Model questions
Model, grammar and limits
Plans a prospective study of one mean with known sigma and a normal model, or two independent proportions using Cohen's arcsine h. This is an explicit approximation, not t-test power with unknown sigma or an exact binomial design. You choose the effect size, alpha and allocation; the smallest whole n that meets the model's power is returned. Group 1 can have at most 10 million. There is no guarantee that the study is valid. δ=|Δ|/σ; h=2arcsin√p₁−2arcsin√p₂; π=Φ(δ/SE−zα)+Φ(−δ/SE−zα)
Unit
Planning model; Planned mean difference; Declared standard deviation; Planned first proportion (1); Planned second proportion (1); n₂ / n₁ allocation (1); Significance level α (1); Target power (1); Planning alternative. Limits: 256000 raw data characters, 5000 source records and 50000 cells in total; decimals up to 48 characters; up to 20 groups or contributions and 50 columns. Limits for exact and bootstrap methods are stated with each tool. Parsing and resource checks run before the calculation, and the worker stops after 15 seconds. Editing, canceling or resetting discards pending results.
Model results
Check assumptions, ties and missing values before drawing conclusions. Results show 10 significant digits; CSV keeps the numeric values and units. Exact enumeration means exact counts, not exact displayed decimals. Numerical tail zeros, floors and unavailable intervals are labeled. Nothing here is a diagnosis, proof of causation or validity approval.
Download input backup
Your data stays in this browser. The calculation runs in a local worker, and CSV and backup files are local downloads you choose to make. Your data is not sent anywhere or saved silently, so keep your original data. Input data, formulas and filenames are never sent. Only with your optional consent, Refentra sends aggregate counts of actions and outcomes, without input content.