Sample Size and Power Calculators
log-rank sample size statistical calculator
Log-rank Sample Size Statistical Calculator
Log-Rank Sample Size Calculator estimate required events and total sample size for a two-group log-rank test. It is part of the Salar Cafe collection of free statistical calculators.
Quick Answer
The log-rank sample size statistical calculator estimate required events and total sample size for a two-group log-rank test.
Sample Size and Power Calculators
Log-Rank Sample Size Statistical Calculator
Estimate required events and total sample size for a two-group log-rank test.
Calculated result
When to use
Estimate required events and total sample size for a two-group log-rank test.
Formula or algorithm
Schoenfeld events=(z_alpha/2+z_power)²/[log(HR)² p(1-p)]; total sample divides events by expected event probability.
Assumptions and limits
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.
Use Raw Data, Excel, or CSV
Upload XLSX, CSV, TSV, TXT, JSON, or pasted data where applicable; inspect cleaning, select the required variable roles, and review mapped inputs before calculation.
Uploaded files are processed locally in the browser. The cleaning report appears before variable dropdowns, and the selected cleaned columns are placed into this exact calculator rather than a generic fallback method.
About the Log-Rank Sample Size Calculator
Estimate required events and total sample size for a two-group log-rank test. 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 your browser. Submitted values are validated for the required numeric range, data shape, units, and method-specific restrictions before a result is 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 panel shows the final answer together with the intermediate quantities needed to audit the calculation. Depending on this 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 Example
Load the verified example or upload cleaned data, assign variable roles, calculate, and review the method-specific result and chart.
| Input | Example value |
|---|---|
| Target hazard ratio | 0.7 |
| Target power | 0.8 |
| Alpha | 0.05 |
| Group 2 / Group 1 allocation ratio | 1 |
| Expected overall event probability | 0.7 |
How to Use the Calculator
- Confirm that the calculator title and method match the quantity, test, conversion, or planning question you need to solve.
- Enter values with compatible units and the requested sample, group, matrix, count, date, or option format.
- Select Example Data to inspect a valid input layout, or enter your own values and select Calculate.
- Review the result table, formula, worked substitutions, warnings, and interpretation rather than using only the headline number.
- Use Copy Result or Download CSV when you need a reusable record of the displayed calculation.
Understanding the Result
Interpret the estimate, uncertainty, test statistic, p-value, effect size, and diagnostics for the selected variables and design.
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.
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.
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.
Related Search Questions and Calculator Terms
This page answers the following closely related statistical calculator searches without creating duplicate competing URLs:
- log-rank sample size calculator
- statistical calculator
- statistical calculators
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.