OBJECTIVE To provide a practical guidance for the analysis of N-of-1 trials by comparing four commonly used models. METHODS The four models, paired t-test, mixed effects model of difference, mixed effects model and meta-analysis of summary data were compared using a simulation study. The assumed 3-cycles and 4-cycles N-of-1 trials were set with sample sizes of 1, 3, 5, 10, 20 and 30 respectiv...

BACKGROUND In this article, we discuss the purpose of sample size calculation in clinical trials, the need for it, and the methods by which it is accomplished. Study samples that are either too small or too large are unacceptable, for clinical, methodological, and ethical reasons. The physicians participating in clinical trials should be directly involved in sample size planning, because their ...

The importance of sample size evaluation in clinical trials is reviewed and a general method is presented from which specific equations are derived for sample size determination or the analysis of power for a wide variety os statistical procedures. The method is discussed and illustrated in relation to the t test, tests for proportions, tests of survival time, and tests for correlations as they...

Normatively, a statistical pairwise comparison is a function of the mean, standard deviation (SD), and sample size of the data. In our experiment, 203 undergraduates compared product pairs and judged their confidence thatone product was better than the other. We experimentally manipulated (within subjects) theaverage productratings, the number of raters (sample size), and the SD of the ratings....

The Kids and Communities Count Farm Safety Lesson is a follow-up to our Kids Count Lesson that used the North American Guidelines for Children's Agricultural Tasks (NAGCAT) and was previously delivered to nearly 2,000 fifth-grade students in Hillsborough County, Florida. This year, the lesson was administered in two migrant schools and included a parent survey and a presentation of the lesson i...

Materials and Methods: This Randomized Control Trial consists of two experimental and control groups. The experimental group received intervention based on Health Action Model. Control group did not receive any intervention except participating in the current safety courses of company. The sample size was 270 worker who were randomly selected and divided into two experimental (n=135) and contro...

One of the simplest and most widely used multiple comparison tests is the Bonferroni adjustment (test). It is applicable to the following situations: 1) Regardless of whether or not the sample sizes of each group are equal. 2) When the family of interest is the particular set of comparisons (not all pair-wise comparisons). We can easily obtain the results of the Bonferroni comparison by multipl...

Power is defined as the probability of correctly detecting an effect. It is often noted , where the converse, ̄ is the probability of a type-II error (not rejecting H0 when there is an effect). When planning a new experiment, it is generally recommended to have a power of at least .80. Suppose that your design has very little power and suppose further that you found a significant effect. Since y...

Many Six Sigma practitioners use “Student’s” independent two-sample t-test when investigating differences in means. This type of test is based upon drawing random samples from two independent normal (Gaussian) distributions. Often, however, the assumption of normality and/or random sampling is violated. This article discusses when and why the two-sample t-test may be considered robust to these ...

Aims / Objectives: To introduce a statistical test, which is mixture of the one-sample t-test and Wilcoxon signed-rank test depends on sample kurtosis, using data from symmetric univariate distribution with finite variance.
 Study Approach: Computer simulation coverage probabilities power calculations either or based software R.
 Methodology: Data are generated differing sizes Normal,...