Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Sample sizes for clinical trials with normal data.

Steven A Julious1

  • 1Institute of General Practice and Community Care, Community Science Centre, Northern General Hospital, Herries Road, Sheffield, S5 7AU, U.K. S.A.Julious@sheffield.ac.uk

Statistics in Medicine
|June 15, 2004
PubMed
Summary
This summary is machine-generated.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Considerations for improving non-inferiority trials.

Lancet (London, England)·2026
Same author

A letter intervention to GPs practices to promoting prescription uptake in school-age children with asthma during summer holidays (TRAINS study): a pragmatic cluster randomised controlled trial.

NPJ primary care respiratory medicine·2026
Same author

Mesenchymal intravenous stromal cell infusions in children with recessive dystrophic epidermolysis bullosa: MissionEB protocol for a randomised, double-blinded, placebo-controlled, two-centre, crossover trial with an internal phase I dose de-escalation phase and open-label extension.

BMJ open·2025
Same author

Analysis of recurrent events in cluster randomised trials: The PLEASANT trial case study.

Statistical methods in medical research·2025
Same author

Reporting and communication of sample size calculations in adaptive clinical trials: a review of trial protocols and grant applications.

BMC medical research methodology·2024
Same author

Assurance methods for designing a clinical trial with a delayed treatment effect.

Statistics in medicine·2024

This article details sample size calculations for clinical trials, covering superiority, equivalence, and non-inferiority objectives. It explains how trial goals impact hypothesis formulation and sample size determination, offering practical tables and examples.

Area of Science:

  • Clinical Trials Methodology
  • Biostatistics
  • Statistical Power Analysis

Background:

  • Accurate sample size calculation is crucial for clinical trial validity and efficiency.
  • Different trial objectives necessitate distinct statistical approaches and sample size considerations.
  • Understanding the interplay between hypotheses and sample size is fundamental in study design.

Purpose of the Study:

  • To provide a comprehensive overview of sample size calculations for parallel group and cross-over studies.
  • To demonstrate sample size derivation for various trial objectives including superiority, equivalence, non-inferiority, bioequivalence, and precise estimation.
  • To illustrate the influence of trial objectives on null and alternative hypotheses and subsequent calculations.

Main Methods:

Related Experiment Videos

  • Derivation of sample size formulas for Normal data in parallel group and cross-over designs.
  • Explanation of how different trial objectives (e.g., superiority, equivalence) shape hypothesis testing.
  • Utilization of Type I and Type II error rates in sample size determination.

Main Results:

  • Sample size calculations are presented for demonstrating superiority, equivalence, non-inferiority, and bioequivalence.
  • The impact of different trial objectives on the formulation of null and alternative hypotheses is clearly demonstrated.
  • Sample size tables and worked examples are provided for practical application.

Conclusions:

  • The choice of trial objective fundamentally influences sample size calculations through hypothesis definition.
  • This article provides a valuable resource for researchers designing clinical trials requiring precise sample size determination.
  • The presented methods and examples facilitate appropriate sample size selection for various study designs and statistical objectives.