Sample Size Estimation
Introduction: In general, sample
size calculation is conducted through a pre-study power analysis. Its
purpose is to select an appropriate sample size in achieving a desired power
for correctly detection of a pre-specified clinical meaningful difference at a
given level of significance. This study/tool will provide statistical
procedures for determination of sample size required not only for testing equality, but also for testing non-inferiority/superiority, equivalence (similarity), some survival analysis and phase II clinical trials designs that
are commonly employed at various phases of clinical development. As a handful
tool, it is very useful for clinical scientists and biostatisticians in the
pharmaceutical industry, regulatory agencies, academia, and other researchers.
This program helps users to determine
sample sizes and confidence intervals for a wide range of statistical techniques including means, proportions, survival analysis, phase II clinical trials, epidemiological studies and
some general cases).
DIRECTIONS:
- Choose one of techniques
from the following table
- From the chosen table, please
select one of specified case that you are interested
- A new window will pop up and please read the instructions
on how to use the calaulation tools.
- If
you don’t know which program to use, please feel free to check : User
guidance, definition and terminology
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1. One-Sample
Design 2. Two-Sample
Parallel Design 3. Two-Sample
Crossover Design |
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Note:
Parallel
Design
A parallel design is a
complete randomized design in which each subject receives one and only one
treatment in a random fashion. It does not provide independent estimates for
the intra-subject variability for each treatment. As a result, the assessment
of treatment effect is made based on the total variability, which includes the
inter-subject variability and the intra-subject variability.
Crossover
Design
A crossver design is a
modified randomized block design in which each block receives more than one
treatment at different dosing periods. Subjects are randomly assigned to
receive a sequence of treatments, which contains all the treatments in the
study. The major advantage of a crossover design is that it allows a within
subject comparison between subject variability from the comparison.
