Log-rank Sample Size Statistical Calculator

Log-Rank Sample Size Calculator Workspace Features

• Dedicated Log-Rank Sample Size Calculator variable mapping, calculation contract, result explanation, and diagnostics

About the Log-Rank Sample Size Calculator

Estimate required events and total sample size for a two-group log-rank test. Use Log-Rank Sample Size Calculator to validate target hazard ratio, target power, alpha, group 2 / group 1 allocation ratio, expected overall event probability and report required events, required total sample, group 1 sample, group 2 sample with method-specific calculations, diagnostics, and interpretation. Planning calculators connect effect size, precision, alpha, power, group count, and sample size for the specific design shown.

When to Use the Log-Rank Sample Size Calculator

Estimate required events and total sample size for a two-group log-rank test.

How the Log-Rank Sample Size Calculator Works

Schoenfeld events=(z_alpha/2+z_power)²/[log(HR)² p(1-p)]; total sample divides events by expected event probability.

The calculation runs in the browser. Submitted values are validated for required numeric ranges, data shape, units and method-specific restrictions before results are shown.

Assumptions and Checks

• Use the variable scales and sampling design required by this named statistical method.
• Review missing values, independence or pairing, outliers, and distribution or model assumptions before interpretation.
• Confirm that the selected dependent, independent, grouping, time, item, rater, or matrix variables match the research design.

Required Inputs

• Target hazard ratio (required)
• Target power (required)
• Alpha (required)
• Group 2 / Group 1 allocation ratio (required)
• Expected overall event probability (required)

Results Reported

The result workspace shows the final answer and intermediate quantities needed to audit the calculation. Depending on the method, reported values include:

• Required Events required_events
• Required Total Sample required_total_sample
• Group 1 Sample group_1_sample
• Group 2 Sample group_2_sample

Log-Rank Sample Size Calculator Worked Example

Load the verified example or upload cleaned data, assign variable roles, calculate, and review the method-specific result and chart.

How to Use This Workspace

1. Confirm that the method matches the quantity, hypothesis, model or planning question you need to solve.
2. Enter values with compatible units and the requested sample, group, matrix, count, date or option format.
3. Use Example Data to inspect a valid input layout, or enter your own values and run the calculation.
4. Review the result table, formula, substitutions, warnings and interpretation rather than relying only on the headline number.
5. Copy, download or print the result when you need a reusable analysis record.

Understanding and Reporting the Result

Interpret the estimate, uncertainty, test statistic, p-value, effect size, and diagnostics for the selected variables and design. In the Log-Rank Sample Size Calculator result workspace, interpret Required Events, Required Total Sample, Group 1 Sample, Group 2 Sample together with the method assumptions, warning messages, confidence information, effect magnitude, and diagnostic plots shown for the selected variables.

Planning assumptions should be justified before data collection; attrition, clustering, unequal allocation, and multiplicity may require a larger design.

Keep the entered values, units, selected options and any warning shown beside the result. For a hypothesis test, report the statistic, degrees of freedom where applicable, p-value, alpha level, effect size and decision. For an estimate or conversion, report the formula convention and final unit.

How to Report the Result

Report the method, selected variables, sample information, estimate or statistic, uncertainty, p-value when applicable, and practical conclusion. A reproducible Log-Rank Sample Size Calculator report should identify the mapped variables, valid observations, exclusions or missing-data handling, selected options, principal outputs, uncertainty, diagnostics, and the practical conclusion supported by the analysis.

Accuracy and Limitations

The calculator keeps full browser precision during calculation and rounds only for display. Accuracy still depends on correct inputs and on whether the displayed model represents the real problem. Educational calculators cannot replace required professional review, current official rules, field measurements, laboratory methods or specialist statistical software where those are necessary.

Frequently Asked Questions

What does the Log-Rank Sample Size Calculator calculate?

Estimate required events and total sample size for a two-group log-rank test. Use Log-Rank Sample Size Calculator to validate target hazard ratio, target power, alpha, group 2 / group 1 allocation ratio, expected overall event probability and report required events, required total sample, group 1 sample, group 2 sample with method-specific calculations, diagnostics, and interpretation.

Which formula does the Log-Rank Sample Size Calculator use?

Schoenfeld events=(z_alpha/2+z_power)²/[log(HR)² p(1-p)]; total sample divides events by expected event probability.

What does the log-rank sample size statistical calculator calculate?

Estimate required events and total sample size for a two-group log-rank test.

Can the log-rank sample size statistical calculator upload Excel or CSV data?

Yes. The web application cleans supported files locally in the browser and maps compatible variables to the calculator.

Does the log-rank sample size statistical calculator show a chart?

Yes. The result panel renders a method-specific chart or diagnostic visual from the entered or uploaded data.

How should I report the log-rank sample size statistical calculator result?

Report the method, variables, sample information, estimate or statistic, uncertainty, p-value where applicable, assumptions, and conclusion.